CN107277879A

CN107277879A - A kind of method and base station equipment for supporting seamless switching

Info

Publication number: CN107277879A
Application number: CN201610855465.4A
Authority: CN
Inventors: 许丽香; 王弘; 柯小婉; 格特·扬·范利斯豪特
Original assignee: Beijing Samsung Telecommunications Technology Research Co Ltd; Samsung Electronics Co Ltd
Current assignee: Beijing Samsung Telecom R&D Center; Beijing Samsung Telecommunications Technology Research Co Ltd; Samsung Electronics Co Ltd
Priority date: 2016-04-01
Filing date: 2016-09-27
Publication date: 2017-10-20
Anticipated expiration: 2036-09-27
Also published as: KR102354416B1; US20210274411A1; KR102282308B1; JP7284789B2; US20210029606A1; KR20180123061A; CN113423123B; JP2019516265A; EP3420754A1; US10805852B2; CN107277879B; EP3420754B1; KR20220012425A; CN113423124B; JP2021192552A; KR102512822B1; KR20210095718A; EP3420754A4; US11617115B2; JP6946321B2

Abstract

This application discloses a kind of method and base station equipment for supporting seamless switching, including：Purpose base station receives random access information from UE or RRC connections reconfigure completion message, and purpose base station, which sends data and sent, stops indicating message to source base station, and source base station stopping sends downlink data and stops receiving upstream data from UE to UE and/or source base station.Present invention also offers the method and base station equipment of other several support seamless switchings.The method of the support seamless switching provided by the present invention, can avoid data from sending delay, the unnecessary data transmission of source base station or unnecessary data decryptor, reduce the wasting of resources and energy loss and avoid loss of data and repeat to send.

Description

A kind of method and base station equipment for supporting seamless switching

Technical field

The present invention relates to wireless communication technology, more particularly to a kind of method and base station equipment for supporting seamless switching.

Background technology

Present mobile communication is increasingly intended to provide the user the multimedia service of high rate data transmission, as shown in figure 1, being The system architecture diagram of System Architecture Evolution (SAE).Wherein：

User equipment (UE) 101 is the terminal device for receiving data.Evolved universal terrestrial radio access network (E- UTRAN) 102 be Radio Access Network, including the macro base station (eNodeB/ that access radio network interface is provided for UE NodeB).Mobile management entity (MME) 103 is responsible for UE mobile context, session context and security information.Service network The function that (SGW) 104 mainly provides user plane is closed, MME 103 and SGW 104 are likely to be at same physical entity.Packet count It is responsible for the functions such as charging, Lawful Interception according to network gateway (PGW) 105, same physical entity can also be in SGW 104.Plan Service quality (QoS) strategy and charging criterion are slightly provided with charging regulation function entity (PCRF) 106.GPRS Supporting node (SGSN) 108 for the transmission of data is provided the network node of route and set in UMTS (UMTS) It is standby.Home subscriber server (HSS) 109 be UE local ownership subsystem, be responsible for protection include user equipment current location, The user profile such as address, user security information, the packet data content of user equipment of service node.

Switching flow of the present invention is as described in Figure 2.The method comprising the steps of：

Step 201, source base station (Source eNB) sends handover request message and gives purpose base station (Target eNB).

Step 202, purpose base station sends switching request acknowledgement message to source base station.

Step 203, source base station sends RRC connection reconfiguration messages to UE.Source base station stops sending downlink data to UE.Source Base station stops receiving the upstream data come from UE.UE stops receiving the downlink data that source base station is sent after the message is received, And stop at source base station and send upstream data.

Step 204, source base station (SN) state that transmits Sequence Number is transferred to purpose base station.Source base station starts to forward data to mesh Base station.

Step 205, UE is synchronized to purpose base station.UE accesses purpose cell by RACH RACH.

Step 206, UE transmissions RRC connections reconfigure completion message and give purpose base station.UE starts in purpose base station transceiver number According to.

Step 207, transmitting path handover request message in purpose base station is to MME.

Step 208, MME transmitting pathes handover request ack message gives purpose base station.

Step 209, purpose base station sends UE context release messages to source base station.

Between step 203 to step 206, it is to interrupt that UE up-downgoing data, which are sent, the delay for causing data to send. If source base station continues sending and receiving for data after step 203, UE also continues between step 203 and step 206 Source base station receives downlink data or sends upstream data, and source base station does not know when to stop sending and receiving for data, Until step 209, it can so cause the unnecessary data of source base station to send or data channel monitoring, cause unnecessary resource Waste and energy loss.

In addition, descending, source base station sends data to UE and purpose base station simultaneously after step 203, due to X2 interface It cannot be guaranteed that the sequentially transmission of data, may result in data-bag lost or repeat to receive, and UE can not be detected.Example Such as：PDCP packet 10,11,12 and 3 of the source base station forwarding with PDCP (PDCP) SN it is follow-up without PDCP SN PDCP packets (a, b, c) inform that the next SN to be used in purpose base station is 13. to purpose base station source base stations Due to not transmitting sequentially, the order for 3 PDCP packets that purpose base station is received is (c, a, b).It is correct to be sequentially 10,11,12,(a,13),(b,14),(c,15).The actual data packet that purpose base station is received is 10,11,12, (c, 13), (a, 14),(b,15).The packet that UE is received from source base station is 10,11,12 (a, 13).UE tells purpose base station is next to need hair The PDCP packets SN sent is 14.Therefore purpose base station sends packet (a, 14), and (b, 15) ... is to UE.So UE can be received Twice, packet c can lose packet a.UE PDCP can not detect that packet a is to repeat to send, because two data It is different to wrap a SN.

In the prior art, source base station sends SN states Transfer Message and gives purpose base station, and source base station freezes to send and receive. Source base station tells the next PDCP SN to be used in purpose base station and corresponding by the DL Count in SN state Transfer Messages HFN.After UE is successfully accessed in purpose base station, UE sends PDCP state reports and gives purpose base station, so that under purpose base station is known One to be sent to UE PDCP packets SN.And the corresponding HFN of next PDCP packets is equal in DL Count HFN is smaller by one than the HFN in DL Count.Because next corresponding packets of PDCP SN to be used do not have also necessarily It is transmitted across (source base station has freezed to send and receive state when SN state Transfer Messages are sent) to UE.In enhanced switching During, source base station continues to send downlink data to UE, while source base station after SN states Transfer Message is sent to purpose base station Forward data to purpose base station.Some packets UE have received in source base station, avoids the need for purpose base station and repeats have sent. After UE is successfully accessed in purpose base station, purpose base station can receive the PDCP state reports come from UE, so that purpose base station can be with Know and packet sent since which PDCP SN data to UE, but purpose base station do not know from UE receive it is next The corresponding HFN of PDCP SN of expectation.

Up, source base station informs the up PDCP's in purpose base station by SN state Transfer Messages in existing handoff procedure Reception state and up counting (COUNT), source base station stop the transmission of downlink data and the reception of upstream data.Purpose base station Know the up transmission state from source base station to SGW.Uplink receiving states of the UE in source base station is informed in purpose base station, thus UE from The PDCP packets that next source base station is not received start to send.If source base station continues the hair of data after step 203 Send and receive, after source base station sends SN states Transfer Message to purpose base station, UE is also sending upstream data, and source base station is also connecing Receive the upstream data come from UE.After UE is in the success of purpose base station synchronization or after RRC reconfigures successfully, source is not known in purpose base station Base station receives the uplink receiving state of data from UE, does not also know source base station to SGW up transmission state.Purpose base station according to The up reception state received in the SN state Transfer Messages of step 204 will be no longer valid, so that it cannot be guaranteed that upstream data Seamless transit.

The content of the invention

The invention provides a kind of method and base station equipment for supporting seamless switching, to solve handoff procedure mentioned above In data send delay, the unnecessary data of source base station are sent or unnecessary data decryptor and up-downgoing data are not lost and do not weighed The problem of transmitting again.

A kind of method for supporting seamless switching that the present invention is provided, this method includes：

Source base station sends handover request message and gives purpose base station,

Receive the switching request acknowledgement message that the purpose base station is sent；

RRC connection reconfiguration messages are sent to UE, continues to send downlink data to UE, continues to the upper line number of UE transmissions According to；

The SN states that transmit Sequence Number are transferred to the purpose base station, start to forward data to the purpose base station；

Receive the data that the purpose base station sends and send and stop indicating, the source base station stop sending downlink data to UE, stops receiving upstream data from UE；

Receive the UE context release messages that the purpose base station is sent.

It is preferred that UE is synchronized to behind the purpose base station, the purpose base station sends data transmission stopping and is indicated to source base Stand.

It is that UE is synchronized to behind the purpose base station that the data, which send stopping instruction, what the purpose base station was sent.

It is preferred that also including step：

The source base station sends the 2nd SN states Transfer Message to the purpose base station.

It is preferred that the 2nd SN state Transfer Messages are included：

Ascending packet data convergence protocol sequence number PDCP SN and/or Hyper Frame Number HFN reception state；

Or descending PDCP SN and/or HFN transmission state.

It is preferred that

It is a piece of news or different message that the 2nd SN states Transfer Message and SN states, which are shifted,；

Show that source base station has freezed to send and receive state when sending the 2nd SN state Transfer Messages.

It is preferred that detection need not be sent to UE data at least one in the following manner for purpose base station：

Mode one：Purpose base station is according to the PDCP SN's and/or HFN received in the second state Transfer Message from source base station Transmission state abandons repeated data, directly transmits the data that UE is not received.Described repeated data refers to that source base station is same When be sent to UE and be transmitted to the data of purpose base station；.

Mode two：Purpose base station detects that what is repeated need not be sent to UE's according to from the UE PDCP state reports received Data, abandon repeated data, directly transmit the data that UE is not received；.

Mode three, the PDCP state reports that purpose base station combines the 2nd SN states Transfer Message and received from UE are detected What is repeated need not be sent to UE data, abandon repeated data, directly transmit the data that UE is not received, the 2nd SN shapes State Transfer Message includes PDCP SN and/or HFN transmission state.

It is preferred that sending RRC connection reconfiguration messages to UE, or source base station transmission SN states in the source base station It is transferred to after purpose base station, this method also includes：

Source base station is to UE feeding back uplink data receiving states.

It is preferred that in the source base station sends the step of the 2nd SN states Transfer Message is to purpose base station, in addition to：

Source base station is sent to purpose base station by the uplink receiving state after upstream data is received is stopped；

Or, source base station will stop the uplink receiving state after upstream data is received and up COUNT is sent to purpose base Stand.

It is preferred that sending second after source base station transmission SN states are transferred to purpose base station and in the source base station Before SN states Transfer Message is to purpose base station, or the source base station send SN states be transferred to after purpose base station and The data for receiving the transmission of purpose base station are sent before stopping instruction, and this method also includes：

The upstream data bag that order is received is sent to SGW by source base station, and other packets are transmitted into purpose base station.

It is preferred that during the UE stops at source base station transmission upstream data, in addition to：

Purpose base station is according to the uplink receiving state received, the data forwarded with reference to the source base station received from source base station, mesh Base station update uplink receiving state be sent to UE；

The purpose base station determines that source base station has forwarded data according to end mark.

It is preferred that in the step of source base station forwards data to purpose base station, the data are：

Using the order of the packet of the SN mark forwardings in GTP-U；

Or, the PDCP packets comprising SN, meanwhile, the PDCP packets comprising SN are sent to UE；

Or, comprising the packet for defining Frame Protocol FP, wherein, FP data division includes the PDCP packets of forwarding, The serial number of the packet is included in FP packet header；

Or, PDCP SN packet is included, wherein, the PDCP SN that first packet is used are the particular values set Either setting is false；

Or, PDCP packets are estimated after number by source base station, are sent the packet of estimated number.

It is preferred that after source base station sends RRC connection reconfiguration messages to UE, in addition to：

UE continues to the downlink data of source base station transmission, and continues to send upstream data to source base station；

UE stops receiving downlink data from source base station after purpose base station is synchronized to, and stops sending upper line number to source base station According to.

A kind of base station equipment, the first sending module, first processing module and the first receiving module, wherein,

First sending module, purpose base station is given for sending handover request message；Send RRC connection reconfiguration messages to UE, continues to send downlink data to UE；Send SN states and be transferred to purpose base station, start to forward data to the purpose base station；

First receiving module, the upstream data for continuing to UE；Receive the data transmission that the purpose base station is sent Stop indicating, indicate that first processing module is handled；Receive release message of being composed a piece of writing on the UE that the purpose base station is sent；

First processing module, for controlled under the instruction of receiving module the first sending module stop send downlink data to UE, and control the first receiving module to stop receiving upstream data from UE.

A kind of method for supporting seamless switching, this method includes：

Purpose base station is received after the handover request message of source base station transmission, and sending Handover Request Acknowledge to source base station disappears Breath；

Receive the SN states turn that transmit Sequence Number that the source base station is sent after RRC connection reconfiguration messages are sent to UE Move；

After UE is synchronized to the purpose base station, the purpose base station sends data transmission stopping and is indicated to the source base Stand；

The RRC connections for receiving the UE transmissions reconfigure completion message, to MME transmitting path handover request message；

The path handover request ack message that MME is sent is received, UE context release messages are sent to the source base station.

It is preferred that also including step：

Receive the 2nd SN state Transfer Messages that the source base station is sent；

Detection need not be sent to UE data at least one in the following manner for the purpose base station：

Mode one：Purpose base station is according to the PDCP SN and/or HFN received in the 2nd SN state Transfer Messages from source base station Transmission state repeated data is abandoned, directly transmit the data that UE is not received, described repeated data refers to source base station It is sent to UE simultaneously and is transmitted to the data of purpose base station；

Mode two：Purpose base station detects that what is repeated need not be sent to UE's according to from the UE PDCP state reports received Data, abandon repeated data, directly transmit the data that UE is not received；

It is preferred that after UE is synchronized to the purpose base station, in addition to：

UE stops receiving downlink data from source base station, stops sending upstream data to source base station；

During the UE stops sending upstream data to source base station, in addition to：

The uplink receiving state that purpose base station is fed back according to source base station, the number forwarded with reference to the source base station received from source base station According to purpose base station updates uplink receiving state and is sent to UE；

A kind of base station equipment, including：Second sending module and the second receiving module, wherein,

Second receiving module, the handover request message for receiving source base station transmission；The source base station is received to UE Send RRC connection reconfiguration messages；The RRC connections for receiving the UE transmissions reconfigure completion message；Receive the path that MME is sent Handover request ack message；

Second sending module, for sending switching request acknowledgement message to source base station；The SN states that transmit Sequence Number sent Transfer；After UE is synchronized to the purpose base station, the purpose base station sends data transmission stopping and is indicated to the source base station；To MME sends handover request message；UE context release messages are sent to the source base station.

A kind of method for supporting seamless switching, this method includes：

Source base station sends handover request message and gives purpose base station, and the Handover Request Acknowledge for receiving the purpose base station transmission disappears Breath；

Receive the purpose base station and refer to receiving RRC links and reconfigure the data that are sent after completion message and send stopping Show, stop sending downlink data to UE；

Receive the UE context release messages that the purpose base station is sent.It is preferred that also including step：UE is synchronized to purpose Behind base station, UE stops sending upstream data to source base station；

Or UE transmission RRC connections reconfigure completion message and give purpose base station, UE stops sending upstream data to source base station.

It is preferred that step is also included,

The source base station receives the upstream data stopping reception that purpose base station is sent after the synchronizing information of UE transmissions is received Indicate, the source base station stops receiving upstream data from UE；

In the case where the step is not performed, the source base station receive data send stop indicate message when stop from Data above and below UE receptions.

It is preferred that also including step：

Source base station sends the 2nd SN states Transfer Message and gives purpose base station, the message package containing up PDCP SN and/or HFN reception state.Sent it is preferred that sending RRC connection reconfiguration messages in the source base station to UE, or the source base station SN states are transferred to after purpose base station, and this method also includes：

Source base station is to UE feeding back uplink data receiving states.

The upstream data bag that order is received is sent to SGW by source base station, and other packets are transmitted into purpose base station.Compared with Goodly, during the UE stops at source base station transmission upstream data, in addition to：

Purpose base station is according to the uplink receiving state received, the data forwarded with reference to the source base station received from source base station, mesh Base station update uplink receiving state be sent to UE；The purpose base station determines that source base station has forwarded data according to end mark, The purpose base station sends data transmission stopping and is indicated to source base station.

Using the order of the packet of the SN mark forwardings in GTP-U；

A kind of base station equipment, including：3rd sending module, the 3rd processing module and the 3rd receiving module, wherein,

3rd sending module, purpose base station is given for sending handover request message；Send RRC connection reconfiguration messages to UE, continues to send downlink data to UE；Send SN states and be transferred to purpose base station, start to forward data to the purpose base station；

3rd receiving module, for receiving the switching request acknowledgement message that the purpose base station is sent, continues to UE's Upstream data；Receive the purpose base station and refer to receiving RRC links and reconfigure the data that are sent after completion message and send stopping Show, indicate that the 3rd processing module is handled；Receive release message of being composed a piece of writing on the UE that the purpose base station is sent；

3rd processing module, under the instruction of the 3rd receiving module control sending module stop send downlink data to UE, and control the 3rd receiving module to stop receiving upstream data from UE.

A kind of method for supporting seamless switching, this method includes：

The RRC connections for receiving the UE transmissions reconfigure completion message, send data transmission stopping and are indicated to the source base Stand；

To MME transmitting path handover request message；

It is preferred that also including step：

UE is synchronized to behind purpose base station, and UE stops sending upstream data to source base station；Or UE sends RRC connections and reconfigured Purpose base station is given into message, UE stops sending upstream data to source base station；

The purpose base station determines that source base station has forwarded data according to end mark, and the purpose base station sends data and sent Stopping is indicated to source base station.

A kind of base station equipment, it is characterised in that including：4th sending module and the 4th receiving module, wherein,

4th sending module, for sending switching request acknowledgement message to source base station；Transmit Sequence Number SN states of transmission turn Move；Send data transmission stopping and be indicated to the source base station；To MME transmitting path handover request message；Sent out to the source base station Send UE context release messages；

4th receiving module, the handover request message for receiving source base station transmission；The source base station is received to send out to UE Send RRC connection reconfiguration messages；The RRC connections for receiving the UE transmissions reconfigure completion message；Cut in the path for receiving MME transmissions Change request response.

A kind of method of support seamless switching for dual link, this method includes：

Purpose base station receives macro cell base station MeNB and sends base station increase request message；

Purpose base station sends base station increase request confirmation message to MeNB；

The resource allocation success of purpose base station, MeNB sends base station releasing request message to source base station, and source base station continues to send out Downlink data is served, and source base station forwards the data to purpose base station；

MeNB sends RRC connection reconfiguration messages to UE, and MeNB continues to send downlink data to source base station, under MeNB forwardings Row data give purpose base station；

UE receives RRC connection reconfiguration messages, and UE does not delete or be reset at the configuration of source base station, and between source base station after Continuous up-downgoing data transfer, UE sends RRC connections and reconfigures completion message to MeNB；

MeNB transmissions SeNB reconfigures completion message and gives purpose base station；

UE is synchronized to purpose base station, stops the up-downgoing data transfer between source base station；

Purpose base station sends data transmission stopping and is indicated to MeNB, and MeNB is received to be stopped sending downlink data after the message To source base station, MeNB sends data transmission stopping and is indicated to source base station；

Source base station sends SN states and is transferred to MeNB.

MeNB sends SN states and is transferred to purpose base station.

As seen from the above technical solution, the method for the support seamless switching provided by the present invention, can avoid data from sending out Delay, the unnecessary data transmission of source base station or unnecessary data decryptor are sent, the wasting of resources and energy loss is reduced and avoids Up-downgoing loss of data and repetition are sent.

Brief description of the drawings

Fig. 1 is existing SAE system architecture diagrams；

Fig. 2 is existing switching flow figure；

Fig. 3 supports the schematic diagram of the method one of seamless switching for the present invention；

Fig. 4 supports the schematic diagram of the method two of seamless switching for the present invention；

Fig. 5 supports the schematic diagram of the method three of seamless switching for the present invention；

Fig. 6 supports the method one of seamless switching to be used for the embodiment schematic diagram of dual link for the present invention；

Fig. 7 supports the schematic diagram of the method four of seamless switching for the present invention；

Fig. 8 supports the schematic diagram of the method five of seamless switching for the present invention；

Fig. 9 supports the method four and method five of seamless switching to be used for the embodiment schematic diagram of dual link for the present invention；

Figure 10 supports the schematic diagram of the method six of seamless switching for the present invention；

Figure 11 supports the method six of seamless switching to be used for the embodiment schematic diagram of dual link for the present invention.

Embodiment

In order that the purpose of the application, technological means and advantage are more clearly understood, the application is done below in conjunction with accompanying drawing It is further described.

The present invention supports the method one of seamless switching as described in Figure 3.The method comprising the steps of：

Step 301, source base station (Source eNB) sends handover request message and gives purpose base station (Target eNB).

Step 302, purpose base station sends switching request acknowledgement message to source base station.

Step 303, source base station sends RRC connection reconfiguration messages to UE.Source base station continues to send downlink data to UE.Source Base station continues to the upstream data come from UE.UE continues to the downlink data of source base station transmission after the message is received, And continue to send upstream data in source base station.

In order to solve the problem of upstream data is sent in the present invention, correspondence one of which method, source base station this step it Continue the data receiving state of feeding back uplink afterwards or after step 304 to UE.So UE is known that source base station has been received from UE Which packet.So after the message of UE forwarding steps 307, it is known that since which packet and sends data to purpose Base station.

In order to solve the problem of upstream data is sent in the present invention, second method is that source base station passes through step 306a handles Source base station stops the uplink receiving state after upstream data is received and is sent to purpose base station.So purpose base station just can accurately be known UE stops the uplink receiving state of source base station after upstream data is sent, so that purpose base station can inform that UE, UE do not have source base station There is the packet received to be sent to purpose base station.This method of correspondence, more optimally, it is convenient to omit step 304 is not performed.Source base The up COUNT after source base station stopping upstream data being received by step 306a that stands is sent to purpose base station.Purpose base station root It is known that to unwrap to originate from which PDCP according to the up COUNT received and gives SGW.This method of correspondence, more optimally, source base station SGW can be transmitted directly to the upstream data bag that order is received before step 306 or step 306a after the step 304, Other packets are transmitted to purpose base station.

Step 304, the source base station SN states that transmit Sequence Number are transferred to purpose base station.

In this step, source base station does not freeze to send and receive state.

Source base station starts to forward data to purpose base station.

In order to solve the problem of downlink data in enhanced handoff procedure is lost or repeats to send, there is following several method：

Method one:The order of the packet of forwarding is identified with the SN in GTP-U.Purpose base station is according in GTP-U SN know the sequencing for receiving PDCP packets, and identified according to the next PDCP received from source base station SN There is no PDCP SN first packet, packet below is identified successively.The need for so being received when purpose base station from UE The PDCP packets that next UE is not received can be correctly sent when the next PDCP SN to be sent sent. Even if X2 interface can not be transmitted sequentially, SN of the purpose base station in GTP-U it is also known that the packet that sends of source base station just Really sequentially, so as to mark correct PDCP packets with next PDCP SN, it is to avoid the loss of packet repeats to send.

Method two：Data forwarding is only done in this step, purpose base station is given without sending SN states Transfer Message.Source base Stand and SN is all included in all PDCP packets for being transmitted to purpose base station, the packet with SN will also be sent to UE.Source base Stand and the COUNT of reception state that the PDCP of purpose base station source base station is up and up-downgoing is informed in step 306a.Such purpose Base station is known that source base station stops the descending transmission state of source when downlink data is sent, and source base station stops receiving upper line number Up reception state and source base station are sent to the transmission state of SGW upstream data during according to bag.Institute in the present invention is solved simultaneously The up-downgoing data transmission problem stated, it is ensured that data are not lost and repeat to transmit.

Method three：A Frame Protocol (FP) defined in the packet of purpose base station is forwarded data in source base station.FP number The serial number of the packet comprising forwarding in the PDCP packets of forwarding, the packet header of Frame Protocol is included according to part.Purpose base station root The sequencing for receiving PDCP packets is known according to the SN in FP, and is used according to the next PDCP received from source base station SN identify no PDCP SN first packet, packet below identifies successively.So when purpose base station receive from The PDCP packets that next UE is not received can be correctly sent when next PDCP SN to be sent that UE comes. Even if X2 interface can not be transmitted sequentially, SN of the purpose base station in FP it is also known that the packet that source base station is sent it is correct suitable Sequence, so as to mark correct PDCP packets with next PDCP SN, it is to avoid the loss of packet repeats to send.Method Four：Source base station, which is transmitted in all packets of purpose base station, includes PDCP SN.The data of purpose base station are sent in source base station The next PDCP SN included in bag are false (DUMMY).Purpose base station after the packet of forwarding is received, if It was found that all including SN in all forwarding packets, then the next PDCP SN received are ignored in purpose base station.Or It is a specific value that source base station, which is sent to the next PDCP SN included in the packet of purpose base station,.Purpose base station After SN state Transfer Messages are received, if it find that next PDCP SN are specific values, then receipts are ignored in purpose base station To next PDCP SN.

Method five：Source base station estimation is sent to the number of UE PDCP packets after SN state Transfer Messages.Send Source base station stops sending data to UE after the packet of corresponding number.Source base station gives purpose base in the packet of forwarding corresponding number Included when standing in the packet and do not include PDCP SN in PDCP SN, follow-up packet.Use and receive down in purpose base station The PDCP SN of one represent the packet without PDCP SN received.

Step 305, UE is synchronized to purpose base station.UE accesses purpose cell by RACH RACH.UE stop from Source base station receives downlink data, and UE stops at source base station and sends upstream data.

In order to solve the problem of upstream data is sent in the present invention, the third method is that purpose base station disappears according to step 304 In the uplink receiving state received in breath, the upstream data forwarded with reference to the source base station received from source base station, the renewal of purpose base station Uplink receiving state after renewal is sent to UE by row reception state, purpose base station.If purpose base station is gone back after RACH successes Continue to receive the data forwarded from source base station, purpose base station needs to wait receiving from source base station to receive shape after the data of all forwardings Cheng Xin uplink receiving state.Know that source base station forwards the data that are over according to end mark (end marker) in purpose base station.It is right The third method is answered, step 306 and step 306a can not be performed.

Step 306, purpose base station sends data transmission stopping and is indicated to source base station.The transmission data, which are sent, to be stopped indicating Message package contain UE new eNB UE X2AP (X2 application layer protocols) ID and old eNB UE X2AP ID.Source base station is received Stop sending downlink data after to the message to UE.Source base station stops receiving upstream data from UE.

The data that source base station is transmitted to purpose base station can include SN PDCP packets and the PDCP data without SN Bag, source base station informs the next PDCP SN to be used in purpose base station by step 306a.

By the process, source base station can know that UE stopped data receiver and the transmission in source base station in time, so that source Base station does not need data of eating dishes without rice or wine useless to send or uplink receiving.

The method of the present invention illustrates by taking X2 handoff procedures as an example.If S1 switches, then purpose base station is by moving Dynamic management entity MME sends described data transmission stopping and is indicated to source base station.The data that send send the S1 for stopping indicating Message package contains eNB eNB UE S1AP (S1 Application Part agreement) ID and MME UE S1AP ID.

Step 306a, source base station sends the 2nd SN states Transfer Message and gives purpose base station.The message package contains upstream packet The reception state of data convergence protocol sequence number (PDCP SN) and/or Hyper Frame Number HFN.The message package contains descending PDCP SN And/or HFN transmission state.The message package contains up PDCP SDU reception state, up COUNT and descending COUNT.Institute It can be a piece of news or different message with the SN states transfer in step 304 to state the 2nd SN states Transfer Message.Send Show that source base station has freezed to send and receive state during the second state Transfer Message.

In the method for the invention, the step is optional step, and the step, which can be performed, to be performed.

Step 307, UE transmissions RRC connections reconfigure completion message and give purpose base station.Because after step 303, source base station UE can be sent data to simultaneously and forwards data to purpose base station.So in the data for the forwarding that purpose base station is received from source base station Some possible UE have received.Purpose base station, which has three kinds of modes to detect, need not be sent to UE data：

Mode one：Purpose base station is according to the PDCP SN and/or HFN received in step 306a from source base station transmission state Repeated data is abandoned, the data that UE is not received are directly transmitted.Repeated data herein refers to source base station while being sent to UE and the data for being transmitted to purpose base station.

Mode two：Purpose base station detects that what is repeated need not be sent to UE's according to from the UE PDCP state reports received Data, abandon repeated data, directly transmit the data that UE is not received.Purpose base station is from PDCP state reports under UE expectations One PDCP SN packet starts to send packet to UE.

Mode three, purpose base station combines the PDCP SN and/or HFN that are received in step 306a transmission state and received from UE To PDCP state reports detect that what is repeated need not be sent to UE data, abandon repeated data, directly transmitting UE does not have The data received.That is, purpose base station combines the 2nd SN states Transfer Message and the PDCP state reports received from UE Detect that what is repeated need not be sent to UE data, abandon repeated data, directly transmit the data that UE is not received, described the Two SN state Transfer Messages include PDCP SN and/or HFN transmission state.

Know that next hope is received according to the reception state of the up PDCP packets received in step 306a in purpose base station This information is sent to UE by the packet arrived, purpose base station.So as to which UE is since next packet that network-side is not received It is sent to purpose base station.The up COUNT that purpose base station is received according to step 306a from source base station know it is next need send To SGW packet, so as to avoid sending the packet repeated to SGW or lost data packets.

UE is according to the uplink receiving state received from purpose base station, with reference to the UE data sent in source base station and from source base The feedback that station is received, transmission upstream data bag gives purpose base station since the packet that next source base station is not received.

Step 308, transmitting path handover request message in purpose base station is to MME.

Step 309, MME transmitting pathes handover request ack message gives purpose base station.

Step 310, purpose base station sends UE context release messages to source base station.

So far, that is, the description that the present invention supports seamless handover method one is completed.Source base station can be avoided by this method It is unnecessary to send data to UE and unnecessarily monitor up data channel, and actually UE stops in source base station Downlink reception and up transmission, save interface-free resources and power attenuation；With it, up-downgoing data can also be ensured Continuously transmit, it is to avoid loss of data or repeat transmit.

The present invention supports the method two of seamless switching as described in Figure 4.The method comprising the steps of：

Step 401, source base station sends handover request message and gives purpose base station.

Step 402, purpose base station sends switching request acknowledgement message to source base station.

Step 403, source base station sends RRC connection reconfiguration messages to UE.Source base station continues to send downlink data to UE.Source Base station continues to the upstream data come from UE.UE continues to the downlink data of source base station transmission after the message is received, And continue to send upstream data in source base station.

In order to solve the problem of upstream data is sent in the present invention, correspondence one of which method, source base station this step it Continue the data receiving state of feeding back uplink afterwards or after step 404 to UE.So UE is known that source base station has been received from UE Which packet.So after the message of UE forwarding steps 407, it is known that since which packet and sends data to purpose Base station.

In order to solve the problem of upstream data is sent in the present invention, second method is, source base station by step 406a or Step 408a stops source base station the uplink receiving state after upstream data is received and is sent to purpose base station.So purpose base station is just It can accurately know that UE stops the uplink receiving state of source base station after upstream data is sent, so that purpose base station can inform UE, UE The packet that source base station is not received is sent to purpose base station.This method of correspondence, more optimally, it is convenient to omit step 404 Do not perform.Source base station stops source base station by step 406a or step 408a the up COUNT after upstream data is received and sent Give purpose base station.Purpose base station is known that to unwrap to originate from which PDCP according to the up COUNT received gives SGW.Correspond to this Kind of method, more optimally, source base station can after step 404 with before step 406 or 406a or step 408 or step 408a The upstream data bag that order is received is transmitted directly to SGW, and other packets are transmitted to purpose base station.

Step 404, the source base station SN states that transmit Sequence Number are transferred to purpose base station.

In this step, source base station does not freeze to send and receive state.

Source base station starts to forward data to purpose base station.

Method one:The order of the packet of forwarding is identified with the SN in GTP-U.Purpose base station is according in GTP-U SN know the sequencing for receiving PDCP packets, and marked according to the next PDCP received from source base station SN Know no PDCP SN first packet, packet below is identified successively.So when purpose base station receives the need come from UE The PDCP data that next UE is not received can be correctly sent when the next PDCP SN to be sent to be sent Bag.Even if X2 interface can not be transmitted sequentially, SN of the purpose base station in GTP-U is it is also known that packet that source base station is sent Correct order, so as to mark correct PDCP packets with next PDCP SN, it is to avoid the loss of packet repeats to send out Send.

Method two：Data forwarding is only done in this step, purpose base station is given without sending SN states Transfer Message.Source base Stand and SN is all included in all PDCP packets for being transmitted to purpose base station, the packet with SN will also be sent to UE.Source base Stand and the reception state and up COUNT of the up PDCP packets in purpose base station are informed in step 406a, and pass through step 408a Inform the COUNT of purpose base station down.Or source base station informs that the PDCP of purpose base station source base station is up by step 408a Reception state and the COUNT of up-downgoing.Source is descending when so purpose base station is known that source base station stopping downlink data transmission Transmission state, and reception state up during source base station stopping reception upstream data bag and source base station are sent to the up of SGW The transmission state of data.Simultaneously solve heretofore described up-downgoing data transmission problem, it is ensured that data do not lose and Repeat to transmit.

Method three：A FP defined in the packet of purpose base station is forwarded data in source base station.FP data portion subpackage The serial number of packet comprising forwarding in PDCP packets containing forwarding, the packet header of Frame Protocol.Purpose base station is according in FP SN know the sequencing for receiving PDCP packets, and marked according to the next PDCP received from source base station SN Know no PDCP SN first packet, packet below is identified successively.So when purpose base station is received under UE comes The PDCP packets that next UE is not received can be correctly sent when one PDCP SN to be sent.Even if X2 connects Mouthful can not sequentially transmit, SN of the purpose base station in FP it is also known that the correct order of the packet of source base station transmission so that Correct PDCP packets are marked with next PDCP SN, it is to avoid the loss of packet repeats to send.

Method four：Source base station, which is transmitted in all packets of purpose base station, includes PDCP SN.Mesh is sent in source base station Base station packet in next PDCP SN for including be false (DUMMY).Purpose base station is receiving the number of forwarding After bag, if it find that all including SN in all forwarding packets, then receive next is ignored in purpose base station PDCP SN.Or the next PDCP SN included in the packet that source base station is sent to purpose base station are one specific Value.Purpose base station is after SN state Transfer Messages are received, if it find that next PDCP SN are specific values, then Ignore the next PDCP SN received in purpose base station.

Step 405, UE is synchronized to purpose base station.UE accesses purpose cell by RACH RACH.UE is stopped at Source base station sends upstream data.

In order to solve the problem of upstream data is sent in the present invention, the third method is that purpose base station disappears according to step 404 In the uplink receiving state received in breath, the upstream data forwarded with reference to the source base station received from source base station, the renewal of purpose base station Uplink receiving state after renewal is sent to UE by row reception state, purpose base station.If purpose base station is gone back after RACH successes Continue to receive the data forwarded from source base station, purpose base station needs to wait receiving from source base station to receive shape after the data of all forwardings Cheng Xin uplink receiving state.Know that source base station forwards the data that are over according to end mark (end marker) in purpose base station.It is right The third method is answered, step 406 and step 406a can not be performed.The third method of correspondence, step 408 and step 408a also may be used Not perform.

Step 406, purpose base station sends upstream data stopping reception and is indicated to source base station.The transmission upstream data stops Receive new eNB UE X2AP ID and old eNB UE X2AP ID that the message package indicated contains UE.Source base station receives described Stop receiving upstream data from UE after message.

The method of the present invention illustrates by taking X2 handoff procedures as an example.If S1 switches, then purpose base station is by moving Dynamic management entity MME sends described upstream data stopping reception and is indicated to source base station.The transmission upstream data stops receiving The S1 message packages of instruction contain eNB eNB UE S1AP ID and MME UE S1AP ID.

In the method for the invention, the step is optional step, and the step, which can be performed, to be performed.In the step In the case of not performing, step 406a is also without execution.In the case where the step is not performed, source base station is receiving step Stop receiving upstream data from UE during 408 message.By the process, source base station can know that UE stopped in source base station in time Data send so that source base station does not need data decryptor of eating dishes without rice or wine useless.Step 406a, source base station sends the 3rd SN states and turned Move message and give purpose base station.The message package contains up PDCP SN and/or HFN reception state, and the message package is containing up The reception state of PDCP packets and up COUNT.The 3rd SN states Transfer Message can be with the SN states in step 404 Transfer is a piece of news or different message.Show that source base station has freezed reception state when sending third state Transfer Message. In the method for the invention, the step is optional step, and the step, which can be performed, to be performed.

Step 407, UE transmissions RRC connections reconfigure completion message and give purpose base station.Since after step 403, source base station UE can be sent data to simultaneously and forwards data to purpose base station.So in the data for the forwarding that purpose base station is received from source base station Some possible UE have received.Purpose base station detects that what is repeated does not need according to from the UE PDCP state reports received UE data are sent to, repeated data is abandoned, directly transmits the data that UE is not received.Purpose base station is from PDCP state reports The packet for next PDCP SN that UE expects starts to send packet to UE.UE stops receiving downlink data from source base station.

Know that next hope is received according to the reception state of the up PDCP packets received in step 406a in purpose base station This information is sent to UE by the packet arrived, purpose base station.So as to which UE is since next packet that network-side is not received It is sent to purpose base station.The up COUNT that purpose base station is received according to step 406a from source base station know it is next need send To SGW packet, so as to avoid sending the packet repeated to SGW or lost data packets.

Step 408, purpose base station sends data transmission stopping and is indicated to source base station.The transmission data, which are sent, to be stopped indicating Message package contain UE new eNB UE X2AP ID and old eNB UE X2AP ID.Source base station stops after receiving the message Downlink data is only sent to UE.If step 406 is not performed, source base station also stops receiving upstream data from UE.

Source base station is transmitted to PDCP of the packet of purpose base station containing the PDCP packets that can include SN and without SN Packet, source base station informs the next PDCP SN to be used in purpose base station by step 408a.

By the process, source base station can know that UE stopped the data receiver in source base station in time, so that source base station is not Need transmission downlink data of eating dishes without rice or wine useless.

Purpose base station, which has three kinds of modes to detect, need not be sent to UE data：

Mode one：Purpose base station is according to the PDCP SN and/or HFN received in step 408a from source base station transmission state Repeated data is abandoned, the data that UE is not received are directly transmitted.Repeated data herein refers to source base station while being sent to UE and the data for being transmitted to purpose base station.

Mode three, purpose base station combines the PDCP SN and/or HFN that are received in step 408a transmission state and received from UE To PDCP state reports detect that what is repeated need not be sent to UE data, abandon repeated data, directly transmitting UE does not have The data received.That is, purpose base station combines the 2nd SN states Transfer Message and the PDCP state reports received from UE Detect that what is repeated need not be sent to UE data, abandon repeated data, directly transmit the data that UE is not received, described the Two SN state Transfer Messages include PDCP SN and/or HFN transmission state.

Know that next hope is received according to the reception state of the up PDCP packets received in step 406a in purpose base station This information is sent to UE by the packet arrived, purpose base station.So as to UE purpose base station from network-side do not receive it is next Packet starts to send.The up COUNT that purpose base station is received according to step 406a from source base station know it is next need send To SGW packet, so as to avoid sending the packet repeated to SGW or lost data packets.

The method of the present invention illustrates by taking X2 handoff procedures as an example.If S1 switches, then purpose base station is by moving Dynamic management entity MME sends described data transmission stopping and is indicated to source base station.The data that send send the S1 for stopping indicating Message package contains eNB eNB UE S1AP ID and MME UE S1AP ID.

Step 408a, source base station sends the 4th SN states Transfer Message and gives purpose base station.The message package contains descending PDCP SN and/or HFN transmission state, the message package contains descending COUNT.The 4th SN states Transfer Message can and step SN states transfer in 404 is a piece of news or different message.Show that source base station freezes when sending the 4th state Transfer Message Transmission state is tied.If step 406 and step 406a are not performed, the message also includes up PDCP SDU reception state With up COUNT, also show that source base station has freezed reception state when sending the 4th state Transfer Message.

Step 409, transmitting path handover request message in purpose base station is to MME.

Step 410, MME transmitting pathes handover request ack message gives purpose base station.

Step 411, purpose base station sends UE context release messages to source base station.

So far, that is, the description that the present invention supports seamless handover method two is completed.Source base station can be avoided by this method It is unnecessary to send data to UE and unnecessarily monitor up data channel, and actually UE stops in source base station Downlink reception and up transmission, save interface-free resources and power attenuation；With it, up-downgoing data can also be ensured Continuously transmit, it is to avoid loss of data or repeat transmit.

The present invention supports the method three of seamless switching as described in Figure 5.The method comprising the steps of：

Step 501, source base station sends handover request message and gives purpose base station.

Step 502, purpose base station sends switching request acknowledgement message to source base station.

Step 503, source base station sends RRC connection reconfiguration messages to UE.Source base station continues to send downlink data to UE.Source Base station continues to the upstream data come from UE.UE continues to the downlink data of source base station transmission after the message is received, And continue to send upstream data in source base station.

In order to solve the problem of upstream data is sent in the present invention, correspondence one of which method, source base station this step it Continue the data receiving state of feeding back uplink afterwards or after step 504 to UE.So UE is known that source base station has been received from UE Which packet.So after the message of UE forwarding steps 507, it is known that since which packet and sends data to purpose Base station.

In order to solve the problem of upstream data is sent in the present invention, second method is that source base station passes through step 508a handles Source base station stops the uplink receiving state after upstream data is received and is sent to purpose base station.So purpose base station just can accurately be known UE stops the uplink receiving state of source base station after upstream data is sent, so that purpose base station can inform that UE, UE do not have source base station There is the packet received to be sent to purpose base station.This method of correspondence, more optimizes, it is convenient to omit step 504 is not performed.Source base The up COUNT after source base station stopping upstream data being received by step 508a that stands is sent to purpose base station.Purpose base station root It is known that to unwrap to originate from which PDCP according to the up COUNT received and gives SGW.This method of correspondence, more optimizes, source base station SGW can be transmitted directly to the upstream data bag that order is received before step 508 or 508a after step 504, it His packet is transmitted to purpose base station.

Step 504, the source base station SN states that transmit Sequence Number are transferred to purpose base station.

In this step, source base station does not freeze to send and receive state.

Step 505, source base station starts to forward data to purpose base station.

Method two：Step 504 source base station need not be performed and send process of the SN states Transfer Message to purpose base station.Source base Stand and SN is all included in all PDCP packets for being transmitted to purpose base station, the packet with SN will also be sent to UE.Source base Stand and the COUNT of reception state that the PDCP of purpose base station source base station is up and up-downgoing is informed in step 508a.Such purpose Base station is known that source base station stops the descending transmission state of source when downlink data is sent, and source base station stops receiving upper line number Up reception state and source base station are sent to the transmission state of SGW upstream data during according to bag.Institute in the present invention is solved simultaneously The up-downgoing data transmission problem stated, it is ensured that data are not lost and repeat to transmit.

Step 506, UE is synchronized to purpose base station.UE accesses purpose cell by RACH RACH.

In order to solve the problem of upstream data is sent in the present invention, the third method is that purpose base station disappears according to step 504 In the uplink receiving state received in breath, the upstream data forwarded with reference to the source base station received from source base station, the renewal of purpose base station Uplink receiving state after renewal is sent to UE by row reception state, purpose base station.If purpose base station is gone back after RACH successes Continue to receive the data forwarded from source base station, purpose base station needs to wait receiving from source base station to receive shape after the data of all forwardings Cheng Xin uplink receiving state.Know that source base station forwards the data that are over according to end mark (end marker) in purpose base station.It is right The third method is answered, step 508 and step 508a can not also be performed.

Step 507, UE transmissions RRC connections reconfigure completion message and give purpose base station.Since after step 403, source base station UE can be sent data to simultaneously and forwards data to purpose base station.So in the data for the forwarding that purpose base station is received from source base station Some possible UE have received.Purpose base station detects that what is repeated does not need according to from the UE PDCP state reports received UE data are sent to, repeated data is abandoned, directly transmits the data that UE is not received.Purpose base station is from PDCP state reports The packet for next PDCP SN that UE expects starts to send packet to UE.UE stops receiving downlink data, UE from source base station Stop at source base station and send upstream data.

Step 508, purpose base station sends data transmission stopping and is indicated to source base station.The transmission data, which are sent, to be stopped indicating Message package contain UE new eNB UE X2AP ID and old eNB UE X2AP ID.Source base station stops after receiving the message Downlink data is only sent to UE.Source base station stops receiving upstream data from UE.

The data that source base station is transmitted to purpose base station can include SN PDCP packets and the PDCP data without SN Bag, source base station informs the next PDCP SN to be used in purpose base station by step 508a.

Step 508a, source base station sends the 5th SN states Transfer Message and gives purpose base station.The message package contains up PDCP SN and/or Hyper Frame Number (HFN) reception state.The message package contains descending PDCP SN and/or HFN transmission state.It is described to disappear Breath includes up PDCP SDU reception state, up COUNT and descending COUNT.The 5th SN states Transfer Message can be with It is a piece of news or different message with the SN states transfer in step 504.Show source when sending the second state Transfer Message Freeze to send and receive state in base station.

Know that next hope is received according to the reception state of the up PDCP packets received in step 508a in purpose base station This information is sent to UE by the packet arrived, purpose base station.So as to which UE is since next packet that network-side is not received It is sent to purpose base station.The up COUNT that purpose base station is received according to step 508a from source base station know it is next need send To SGW packet, so as to avoid sending the packet repeated to SGW or lost data packets.

Step 509, transmitting path handover request message in purpose base station is to MME.

Step 510, MME transmitting pathes handover request ack message gives purpose base station.

Step 511, purpose base station sends UE context release messages to source base station.

So far, that is, the description that the present invention supports seamless handover method three is completed.Source base station can be avoided by this method It is unnecessary to send data to UE and unnecessarily monitor up data channel, and actually UE stops in source base station Downlink reception and up transmission, save interface-free resources and power attenuation.

Fig. 6 supports the method one of seamless switching to be used for the embodiment schematic diagram of dual link for the present invention.Including step：

Step 601, master base station (MeNB) sends the second base station (SeNB) increase request message and gives purpose SeNB (T-SeNB).

Step 602, T-SeNB sends SeNB increase request confirmation messages to MeNB.

Step 603, if T-SeNB resource allocation success, MeNB sends SeNB releasing requests message and gives source SeNB (S- SeNB).If necessary to data forwarding, MeNB provides data forwarding addresses to S-SeNB.S-SeNB is received after SeNB release messages Continue to send data to UE.Source SeNB can start data forwarding.

Correspondence separates (split) carrying, and S-SeNB continues to send upstream data to MeNB.Correspondence second community group (SCG) Carrying, S-SeNB continues to send upstream data to SGW.

For SCG carryings, S-SeNB continues the data receiving state of feeding back uplink to UE after this step.So UE is just Know which packet S-SeNB have received from UE.Which so after the message of UE forwarding steps 608, it is known that from number Purpose base station is sent data to according to the beginning is unwrapped.

It is used as another method of the present invention, it is convenient to omit this step is not performed, such S-SeNB may proceed to send number According to UE.

Step 604, S-SeNB forwards data to T-SeNB.Correspondence split carryings, S-SeNB forwards data to MeNB, by MeNB is transmitted to T-SeNB., can be as split carryings for SCG carryings, S-SeNB is transmitted to T-SeNB by MeNB, Or S-SeNB is directly forwarded to T-SeNB.Depending on realization, S-SeNB forwards data to T-SeNB can be after step 603 Whenever perform.

Step 605, MeNB sends RRC connection reconfiguration messages to UE.MeNB continues to send downlink data to S-SeNB.Together When MeNB converting downlink data to T-SeNB.

Step 606, UE receives RRC connection reconfiguration messages.UE does not delete or is reset at S-SeNB configuration.UE continues to connect Receive the downlink data that S-SeNB is sent.UE continues to send upstream data to S-SeNB.UE sends RRC connections and reconfigures completion message To MeNB.

Step 607, MeNB sends SeNB and reconfigures completion message to T-SeNB.

Step 608, UE is synchronized to T-SeNB.

UE stops receiving downlink data from S-SeNB, and UE stops at S-SeNB and sends upstream data.

Step 609, T-SeNB sends data transmission stopping and is indicated to MeNB.The data that send send disappearing for stopping instruction Breath includes eNB UE X2AP IDs of the T-SeNB for UE eNB UE X2AP ID and the MeNB distribution distributed.MeNB receives described Stop sending downlink data after message to S-SeNB.

Step 610, MeNB sends data transmission stopping and is indicated to S-SeNB.The data that send send disappearing for stopping instruction Breath includes eNB UE X2AP IDs of the MeNB for UE eNB UE X2AP ID and the S-SeNB distribution distributed.S-SeNB receives institute State and stop sending downlink data after message to UE.S-SeNB stops receiving upstream data from UE.

By step 609 and the process of step 610, S-SeNB can know that the data that UE stopped in S-SeNB connect in time Receive and send, so that S-SeNB does not need data of eating dishes without rice or wine useless to send or uplink receiving.

Step 611a, S-SeNB transmission SN states are transferred to MeNB.

Step 611b, MeNB transmission SN states are transferred to T-SeNB.

For SCG carryings, step 611a and step 611b have performed following benefit after step 610：T-SeNB is with regard to energy Accurate to know the reception state that UE stops S-SeNB after upstream data is sent, so that T-SeNB can inform UE, UE is S-SeNB The packet not received is sent to T-SeNB.This method of correspondence, more optimally, S-SeNB can after step 603 and The upstream data bag that order is received before step 610 is transmitted directly to SGW, and other packets are transmitted to T-SeNB.

For SCG carryings, T-SeNB knows according to the reception state of the up PDCP packets received in step 611b message This information is sent to UE by the next packet for wishing to receive in road, T-SeNB.So as to UE from network-side do not receive it is next Individual data, which are unwrapped to originate, gives T-SeNB.T-SeNB knows next according to step 611b from the S-SeNB up COUNT received Need to be sent to SGW packet, so as to avoid sending the packet repeated to SGW or lost data packets.

For split carryings, whenever step 611a and step 611b can perform after step 603.

For SCG carryings, step 611a and step 611b can be performed after step 610 is received.

The detailed description of the step unrelated with the application main contents is omitted here, such as between MeNB and MME ERAB changes instruction process.

So far, that is, completing the application supports seamless handover method one to be used for the description of dual link embodiment.Pass through the party Method can avoid S-SeNB is unnecessary from sending data to UE and unnecessarily monitor up data channel, and actually UE Downlink reception and up transmission are stopped in S-SeNB, interface-free resources and power attenuation are saved；With it, may be used also To ensure continuously transmitting for up-downgoing data, it is to avoid loss of data repeats to transmit.

The present invention supports the method four of seamless switching as described in Figure 7.The method comprising the steps of：

Step 701, source base station (Source eNB) sends handover request message and gives purpose base station (Target eNB).

In this method, source base station determines to use enhanced handoff procedure.Enhanced switching refers to that 3GPP Rel-14 are discussed And source base station keep connection handover scheme.Concretely, enhanced handoff procedure refers to the source in hand-off execution process Base station is also sending downlink data to UE, and receives upstream data from UE.More specifically RRC connections are have sent in source base station After reconfiguration message or after source base station have sent RRC connection reconfiguration messages and purpose base station receives UE RACH and connect Before entering or after source base station have sent RRC connection reconfiguration messages and purpose base station receives UE RRC connections and reconfigured Source base station is also sending downlink data to UE before, and receives upstream data from UE.The implication and 3GPP of hand-off execution process It is identical defined in TS36.300.Source base station is determined using enhancing according to itself to strengthening the support of handoff procedure and UE ability Handoff procedure.Or source base station according to itself to strengthen handoff procedure support, UE ability and purpose base station to enhancing Handoff procedure tenability come determine use enhanced handoff procedure.Source base station can also consider the demand of business simultaneously (such as quality of service ensure Qos information) determines to use enhanced handoff procedure.Source base station is also conceivable to other information Determine using enhanced handoff procedure without influenceing the main contents of the present invention.Source base station obtains branch of the UE to enhancing switching from UE Hold ability.UE supports the ability of enhanced switching to refer to that UE after RRC connection reconfiguration messages are received, can not be frozen in source The transmission reception state of base station, the information in two L2 of source base station layer is not emptied, can continue to receive data or transmission from source base station Data.Source base station sets up process to know that purpose base station switched to enhanced by the configuration or X2 of operation and maintenance (O＆M) The tenability of journey.The method that correspondence sets up process by X2, sets up request in X2 and X2 sets up to include in response message and sent Tenability of the base station of the message to enhanced handoff procedure.Receive X2 foundation request or X2 sets up the base station of response message Tenability of the opposite end base station that holding is received to enhanced handoff procedure.

There are following methods that purpose base station can be allowed to know that source base station has used enhanced handoff procedure in the present invention.

Method one, source base station comprising enhanced indication message in handover request message by allowing purpose base station to know This switching is enhanced handoff procedure.

Method two：Comprising tenabilities of the UE to enhancing switching in handover request message, purpose base station is according to source base station This handoff procedure, which is enhanced cuts, to be known to the tenability of enhancing switching to the tenability and UE for strengthening handoff procedure Change process.Source base station obtains tenabilities of the UE to enhancing switching from UE.The configuration that purpose base station passes through operation and maintenance (O＆M) Or X2 sets up process to know tenability of the source base station to enhanced handoff procedure.The method that correspondence sets up process by X2, Request is set up in X2 and X2 is set up in response message comprising support energy of the base station to enhanced handoff procedure for sending the message Power.Receive that X2 sets up request and X2 sets up the base station of response message and keeps the opposite end base station that receives to the branch of enhanced handoff procedure Hold ability.This method of correspondence, it is assumed that if source base station supports enhanced handoff procedure, when the source base station is initiated to supporting to increase During the UE switched by force handoff procedure, enhanced handoff procedure will be initiated.Or if enhancing is supported in source base station and purpose base station Handoff procedure, when the source base station initiate to support strengthen switching UE handoff procedure when, enhanced switching will be initiated Process.

Source base station can notify purpose base station strengthens to be unwrapped in handoff procedure from first data for being transmitted to purpose base station The number for the most packets for giving UE is originated, the packet number of e.g. PDCP SN maximum magnitudes subtracts 1, or PDCP The packet number of SN maximum magnitudes or other.If such as PDCP SN are to subtract 1 from 0 to 127, PDCP SN maximum magnitudes The packet of number is 127 PDCP SDU or PDU.

Step 702, purpose base station sends switching request acknowledgement message to source base station.

If purpose base station have received enhanced indication message from source base station, purpose base station refers to enhanced switching Show that information is included in the RRC containers Container of switching request acknowledgement message.By RRC Container by described increasing Strong indication message is sent to UE.

Step 703, source base station sends RRC connection reconfiguration messages to UE.Indicated in the message comprising enhanced switching Information.The enhanced handoff procedure of correspondence, source base station continues to send downlink data to UE.A kind of method of the correspondence present invention, source base The packet that station continues to be sent to UE is to unwrap a beginning up to PDCP SN most from first data for being transmitted to purpose base station The a wide range of packet for subtracting 1 number.First packet that such as source base station is transmitted to purpose base station is that PDCP SN are equal to 5, HFN is 10, then it is 11 that source base station is up to PDCP SN equal to 3, HFN to the UE packets sent.

Source base station continues to the upstream data come from UE.UE continues to source base station transmission after the message is received Downlink data, and continue to send upstream data in source base station.What UE was included according to receiving in the RRC connections reconfiguration message Enhanced indication message knows that the handoff procedure is enhanced handoff procedure, thus continue source base station data send and Receive.

In order to solve the problem of upstream data is sent in the present invention, correspondence one of which method, source base station this step it Continue the data receiving state of feeding back uplink afterwards or after step 704 to UE.So UE is known that source base station has been received from UE Which packet.So after the message of UE forwarding steps 706, it is known that since which packet and sends data to purpose Base station.

Step 704, the source base station SN states that transmit Sequence Number are transferred to purpose base station.

In this step, source base station does not freeze to send and receive state.

Source base station starts to forward data to purpose base station.The downlink data for being sent to UE is also transmitted to purpose base by source base station Stand.Source base station from the UE upstream data bags received being transmitted to purpose base station.A kind of method is that source base station disappears the transfer of SN states Received after breath tactic does not receive upstream data bag sequentially and is forwarded to purpose base station.Another method is source base Stand and the packet sequentially received is sent to SGW, the packet not received sequentially is transmitted to purpose base station.

Step 705, UE is synchronized to purpose base station.UE accesses purpose cell by RACH RACH.

In the present invention, UE can stop receiving downlink data from source base station in this step, stop at source base station and send up Data.It can also stop receiving downlink data from source base station in step 706, stop at source base station and send upstream data.

In order to solve the problem of upstream data is sent in the present invention, purpose base station is upper according to what is received in step 704 message In row reception state and up Count, the upstream data forwarded with reference to the source base station received from source base station, the renewal of purpose base station Uplink receiving state after renewal is sent to UE by row reception state, purpose base station.If purpose base station is gone back after RACH successes Continue to receive the data forwarded from source base station, purpose base station, which needs to wait to receive from source base station, forms new after the data of all forwardings Uplink receiving state.Know that source base station forwards the data that are over according to end mark (end marker) in purpose base station.

Step 706, UE transmissions RRC connections reconfigure completion message and give purpose base station.Since after step 703, source base station Downlink data can be sent simultaneously give purpose base station to UE and converting downlink data.So the forwarding that purpose base station is received from source base station Data in some possible UE have received.Purpose base station, which has following mode to detect, need not be sent to UE number According to：

Know that UE expects next PDCP SN for needing to receive according to from the UE PDCP state reports received in purpose base station. Purpose base station detects that what is repeated need not be sent to UE packet, abandons the data that UE has been received, directly expects from UE Next packet start to be sent to UE.

Only comprising next PDCP for expecting to receive packet in the PDCP state reports that UE is sent to purpose base station SN, not comprising the HFN corresponding to the PDCP SN.

Using the method described in step 701, purpose base station is known that whether this switching is enhanced switched Journey.For enhanced handoff procedure, purpose base station is sent data on UE and/or transmission according to the method for enhanced handoff procedure Row data are to SGW.Purpose base station determines that UE expects next PDCP SN correspondences for receiving packet according to enhanced handoff procedure HFN.

The corresponding packets of PDCP SN for next expectation that purpose base station is included in thinking the PDCP states received from UE First correspondence this PDCP SN preserved in the caching buffer for being purpose base station packet.Because source base station is being transmitted to First data of purpose base station unwrap originate the most packets for giving UE number PDCP SN maximum magnitudes subtract 1 number According to bag number.If first packet PDCP SN=5HFN=10 that such as purpose base station is received from source base station, source base station The packet for being sent to UE is up to PDCP SN=3HFN=11, so the maximum data packet that UE is received from source base station is PDCP SN=3HFN=11.If the data UE that source base station is sent have received, UE expects that next packet received is PDCP SN=4HFN=11, the packet is packets of the corresponding first PDCP SN equal to 4 in the buffer of purpose base station, described The corresponding HFN of packet is 11.If packet some UE that source base station is sent are not received, if such as purpose base station is from UE The PDCP SN of next expectation are 9 in the PDCP states received, and the packet is corresponding first in the buffer of purpose base station PDCP SN are equal to 9 packet, and purpose base station knows that corresponding HFN is 10.If so having identical in the caching of purpose base station PDCP SN packet, then under first packet for confiscating packet SN is in first corresponding UE PDCP state report One packet for needing to be sent to UE, so purpose base station has been known that the corresponding HFN of the packet.

Or, the PDCP SN of next expectation that purpose base station is included in thinking the PDCP states received from UE not away from PDCP SN half PDCP SN scopes in the DL Count received in SN state Transfer Messages, if i.e. PDCP SN maximum Value is N, then N/2s of the PDCP SN of next expectation not away from PDCP SN in DL Count.Source base station have sent SN states When sending data to UE also in compliance with this principle after Transfer Message.It is exemplified below：

● HFN=10 in DL COUNT, PDCP SN=8

● PDCP SN are 7 bits (SN scope is 0..127)

● when purpose base station from the PDCP SN of the UE next expectations received be 73..127 when, HFN=9

● when purpose base station from the PDCP SN of the UE next expectations received be 0..72 when, HFN=10

Source base station is after it have sent SN state Transfer Messages, and source base station is then sent to PDCP SN to UE transmissions data is 72, HFN be to stop sending downlink data packet after 10 to UE.

The enhanced handoff procedure of correspondence, if in the PDCP states that purpose base station is received from UE next expectation PDCP SN is 9, and purpose base station knows that corresponding HFN is 10.If not enhanced switching, purpose base station knows that corresponding HFN is 9.

In order to solve the problem of upstream data is sent in the present invention, purpose base station is upper according to what is received in step 704 message In row reception state and up Count, the upstream data forwarded with reference to the source base station received from source base station, the renewal of purpose base station Uplink receiving state after renewal is sent to UE by row reception state, purpose base station.Purpose base station needs to wait receives from source base station New uplink receiving state is formed after to the data of all forwardings.Purpose base station source is known according to end mark (end marker) Base station forwards the data that are over.The uplink receiving state of generation is sent to UE by purpose base station.

UE is according to the uplink receiving state received from purpose base station, with reference to the UE data sent in source base station and from source base The feedback that station is received, transmission upstream data gives purpose base station since the packet that next source base station is not received.

Step 707, transmitting path handover request message in purpose base station is to MME.

Step 708, MME transmitting pathes handover request ack message gives purpose base station.

Step 709, purpose base station sends UE context release messages to source base station.

So far, that is, the description that the present invention supports seamless handover method four is completed.It can be reduced and switched by this method The break period that data are sent in journey, it is ensured that up-downgoing data are continuously transmitted, it is to avoid loss of data repeats to transmit.Particularly The problem of next PDCP SN for solving purpose base station not know that UE expects corresponding HFN, accordingly even when source base station and purpose base Stand from different manufacturers, also ensure that the interoperability between two base stations, it is ensured that enhanced handoff procedure can workability simultaneously Reduce the break period that data are sent in handoff procedure.

The present invention supports the method five of seamless switching as described in Figure 8.The method comprising the steps of：

Step 801, source base station (Source eNB) sends handover request message and gives purpose base station (Target eNB).

Step 802, purpose base station sends switching request acknowledgement message to source base station.

Step 803, source base station sends RRC connection reconfiguration messages to UE.The enhanced handoff procedure of correspondence, source base station continues Downlink data is sent to UE.Source base station continues to the upstream data come from UE.UE continues to source after the message is received The downlink data that base station is sent, and continue to send upstream data in source base station.

In order to solve the problem of upstream data is sent in the present invention, correspondence one of which method, source base station this step it Continue the data receiving state of feeding back uplink afterwards or after step 804 to UE.So UE is known that source base station has been received from UE Which packet.So after the message of UE forwarding steps 806, it is known that since which packet and sends data to purpose Base station.

Step 804, the source base station SN states that transmit Sequence Number are transferred to purpose base station.

In this step, source base station does not freeze to send and receive state.

Source base station starts to forward data to purpose base station.The downlink data for being sent to UE is also transmitted to purpose base by source base station Stand.Source base station from the UE upstream data packets received being transmitted to purpose base station.A kind of method is that source base station turns SN states Move after message receive tactic or do not receive upstream data bag sequentially and be forwarded to purpose base station.Another method is The packet sequentially received is sent to SGW by source base station, and the packet not received sequentially is transmitted to purpose base station.

Step 805, UE is synchronized to purpose base station.UE accesses purpose cell by RACH RACH.

In the present invention, UE can stop receiving downlink data from source base station in this step, stop at source base station and send up Data.It can also stop receiving downlink data from source base station in step 806, stop at source base station and send upstream data.

In order to solve the problem of upstream data is sent in the present invention, purpose base station is upper according to what is received in step 804 message In row reception state and up Count, the upstream data forwarded with reference to the source base station received from source base station, the renewal of purpose base station Uplink receiving state after renewal is sent to UE by row reception state, purpose base station.If purpose base station is gone back after RACH successes Continue to receive the data forwarded from source base station, purpose base station, which needs to wait to receive from source base station, forms new after the data of all forwardings Uplink receiving state.Know that source base station forwards the data that are over according to end mark (end marker) in purpose base station.

Step 806, UE transmissions RRC connections reconfigure completion message and give purpose base station.Since after step 803, source base station Downlink data can be sent simultaneously give purpose base station to UE and converting downlink data.So the forwarding that purpose base station is received from source base station Data in some possible UE have received.Purpose base station, which has following mode to detect, need not be sent to UE number According to：

In the PDCP state reports that UE is sent to purpose base station comprising it is next expectation receive the PDCP SN of packet with And the HFN corresponding to the PDCP SN.UE can be wrapped only in enhanced handoff procedure in the PDCP states for be sent to base station The HFN corresponding to the PDCP SN of packet is received containing next expectation.If not enhanced switching, purpose base station is according to existing Some principles know that next expectation receives the HFN corresponding to the PDCP SN of packet.

Step 807, transmitting path handover request message in purpose base station is to MME.

Step 808, MME transmitting pathes handover request ack message gives purpose base station.

Step 809, purpose base station sends UE context release messages to source base station.

So far, that is, the description that the present invention supports seamless handover method five is completed.It can be reduced and switched by this method The break period that data are sent in journey, it is ensured that up-downgoing data are continuously transmitted, it is to avoid loss of data repeats to transmit.Particularly The problem of next PDCP SN for solving purpose base station not know that UE expects corresponding HFN, accordingly even when source base station and purpose base Stand from different manufacturers, also ensure that the interoperability between two base stations, it is ensured that enhanced handoff procedure can workability simultaneously Reduce the break period that data are sent in handoff procedure.

Fig. 9 supports the method four and method five of seamless switching to be used for the embodiment schematic diagram of dual link for the present invention.Including Step：

Step 901, master base station (MeNB) sends the second base station (SeNB) increase request message and gives purpose SeNB (T-SeNB).

Master base station determines to use enhanced handoff procedure.The principle of enhanced handoff procedure is identical with described in step 701. Specific in SeNB change procedures, enhanced handoff procedure refers to that source SeNB to UE also in the case where sending in hand-off execution process Row data, and receive upstream data from UE.More specifically master base station after it have sent RRC connection reconfiguration messages or After master base station have sent RRC connection reconfiguration messages and purpose SeNB receive UE RACH access before or in main base Station have sent after RRC connection reconfiguration messages and master base station receive UE RRC connections reconfigure before source SeNB also to UE Downlink data is sent, and upstream data is received from UE.The enhanced switching of support described in the embodiment refers to supporting to increase Strong SeNB change procedures.

Master base station is according to UE ability, master base station to tenability, source SeNB and/or the purpose SeNB of enhancing switching to increasing The tenability switched by force come decide whether use enhanced switching.Master base station is also conceivable to other information such as Qos to determine Surely using enhanced switching without influenceing the main contents of the present invention.

There are following methods that purpose SeNB can be allowed to know in the present invention and used enhanced handoff procedure.

Method one：Master base station by increasing request message in SeNB in allow purpose SeNB comprising enhanced indication message Know that this switching is enhanced handoff procedure.Master base station is determined according to itself to strengthening the support of handoff procedure and UE ability Surely enhanced handoff procedure is used.Source base station can also consider source SeNB and/or purpose SeNB to enhanced handoff procedure simultaneously Tenability come determine use enhanced handoff procedure.Master base station was set up by the configuration or X2 of operation and maintenance (O＆M) Journey knows the tenability of source SeNB and/or purpose SeNB to enhanced handoff procedure.Correspondence sets up the side of process by X2 Method, sets up request in X2 and X2 sets up in response message support of the base station for including the transmission message to enhanced handoff procedure Ability.Receive X2 and set up the opposite end base station for asking to receive with the base station holding that X2 sets up response message to enhanced handoff procedure Tenability.

Method two：Comprising tenabilities of the UE to enhancing switching in SeNB increases request message, if purpose SeNB branch Enhanced handoff procedure is held, purpose SeNB is according to master base station and/or source SeNB to strengthening the tenability and UE of handoff procedure Tenability to enhancing switching knows that this handoff procedure is enhanced handoff procedure.MeNB obtains UE from UE and enhancing is switched Tenability.Purpose SeNB sets up process to know master base station/or source SeNB by the configuration or X2 of operation and maintenance (O＆M) To the tenability of enhanced handoff procedure.The method that correspondence sets up process by X2, sets up request in X2 and X2 sets up response Tenability of the base station to enhanced handoff procedure for sending the message is included in message.Receive X2 and set up request and X2 foundation Tenability of the opposite end base station that the base station holding of response message is received to enhanced handoff procedure.This method of correspondence, it is assumed that If master base station supports enhanced handoff procedure, when the master base station initiates the handoff procedure to supporting the UE for strengthening switching, Enhanced handoff procedure will be initiated.Or if master base station and source SeNB and purpose SeNB support enhanced handoff procedure, when When the master base station initiates the handoff procedure to supporting the UE for strengthening switching, enhanced handoff procedure will be initiated.

Step 902, T-SeNB sends SeNB increase request confirmation messages to MeNB.

If purpose SeNB have received enhanced indication message from MeNB, purpose SeNB indicates enhanced switching Information is included in the RRC Container that SeNB increases request confirmation message.By RRC Container by described enhancing Indication message is sent to UE.RRC Container herein refer to SeNB to MeNB Container.

Step 903, if T-SeNB resource allocation success, MeNB sends SeNB releasing requests message and gives source SeNB (S- SeNB).If necessary to data forwarding, MeNB provides data forwarding addresses to S-SeNB.

There are following methods that source SeNB can be allowed to know that master base station has used enhanced handoff procedure in the present invention.

Method one：Master base station comprising enhanced indication message in SeNB releasing request message by allowing purpose SeNB Know that this switching is enhanced handoff procedure.Master base station decision is identical with step 901 using the method for enhanced handoff procedure, Here repeat no more.

Method two：Comprising tenabilities of the UE to enhancing switching in SeNB increases release message, if source SeNB is supported Enhanced handoff procedure, source SeNB is according to master base station and/or purpose SeNB to the tenability of enhancing handoff procedure and UE pairs The tenability of enhancing switching knows that this handoff procedure is enhanced handoff procedure.MeNB obtains UE to enhancing switching from UE Tenability.Source SeNB sets up process to know SeNB pairs of master base station/or purpose by the configuration or X2 of operation and maintenance (O＆M) The tenability of enhanced handoff procedure.The method that correspondence sets up process by X2, sets up request in X2 and X2 sets up response and disappeared Tenability of the base station to enhanced handoff procedure for sending the message is included in breath.Receive X2 and set up request and X2 foundation sound The base station of message is answered to keep the opposite end base station that receives to the tenability of enhanced handoff procedure.This method of correspondence, it is assumed that such as Fruit master base station supports enhanced handoff procedure, when the master base station initiates the handoff procedure to supporting the UE for strengthening switching, just Enhanced handoff procedure can be initiated.Or if master base station and source SeNB and purpose SeNB support enhanced handoff procedure, work as institute Master base station is stated to initiate, to supporting to strengthen during the UE switched handoff procedure, enhanced handoff procedure will be initiated.

S-SeNB receives that SeNB release messages are follow-up continuous to send data to UE.Source SeNB can start data forwarding.SeNB Continue to receive upstream data from UE.

For SCG carryings, S-SeNB continues the data receiving state of feeding back uplink to UE after this step.So UE is just Know which packet S-SeNB have received from UE.Which so after the message of UE forwarding steps 907, it is known that from number Purpose SeNB is sent data to according to the beginning is unwrapped.

Step 904, MeNB sends RRC connection reconfiguration messages to UE.In the message letter is indicated comprising enhanced switching Breath.MeNB continues to send downlink data to S-SeNB.MeNB converting downlink data are to T-SeNB simultaneously.One kind of the correspondence present invention Method, the packet that source SeNB continues to be sent to UE is to unwrap the beginning up to one from first data for being transmitted to purpose SeNB The packet number of PDCP SN maximum magnitudes subtracts 1.First packet that such as source SeNB is transmitted to purpose SeNB is PDCP It is 10 that SN, which is equal to 5, HFN, then it is 11 that source SeNB is up to PDCP SN equal to 3, HFN to the UE packets sent.

UE receives RRC connection reconfiguration messages.UE does not delete or is reset at S-SeNB configuration.UE continues to S-SeNB The downlink data of transmission.UE continues to send upstream data to S-SeNB.UE according to receive in the RRC connections reconfiguration message wrap The enhanced indication message contained knows that the handoff procedure is enhanced handoff procedure, so as to continue the data hair in source base station Send and receive.

Step 905, UE sends RRC connections and reconfigures completion message to MeNB.

Step 906, MeNB sends SeNB and reconfigures completion message to T-SeNB.

Step 907, UE is synchronized to T-SeNB.

Step 908a, S-SeNB transmission SN states are transferred to MeNB.

Step 908b, MeNB transmission SN states are transferred to T-SeNB.

Step 909, S-SeNB forwards data to T-SeNB.Correspondence split carryings, S-SeNB forwards data to MeNB, by MeNB is transmitted to T-SeNB., can be as split carryings for SCG carryings, S-SeNB is transmitted to T-SeNB by MeNB, Or S-SeNB is directly forwarded to T-SeNB.Depending on realization, S-SeNB forwards data to T-SeNB can be after step 903 Whenever perform.

Because after step 903, source SeNB can send downlink data simultaneously and give purpose SeNB to UE and converting downlink data. So purpose SeNB some possible UE from the data of the source SeNB forwardings received have received.Purpose SeNB is by following Mode detect and need not be sent to UE data：

For SCG carrying, purpose SeNB according to from the UE PDCP state reports received know UE expect it is next need receipts The PDCP SN arrived.Purpose base station detects that what is repeated need not be sent to UE packet, abandons the data that UE has been received, Directly UE is sent to since next packet that UE expects.

For SCG carryings, only number is received comprising next expectation in the PDCP state reports that UE is sent to purpose SeNB According to the PDCP SN of bag, not comprising the HFN corresponding to the PDCP SN.There are following two modes that purpose SeNB can be allowed to know Next expectation receives the HFN corresponding to the PDCP SN of packet：

Mode one：

Using the method described in step 901, purpose SeNB is known that whether this switching is enhanced switched Journey.For enhanced handoff procedure, purpose SeNB is sent data on UE and/or transmission according to the method for enhanced handoff procedure Row data are to SGW.

The corresponding packets of PDCP SN for next expectation that purpose SeNB is included in thinking the PDCP states received from UE First correspondence this PDCP SN preserved in the caching buffer for being purpose SeNB packet.Because source SeNB is being transmitted to Purpose SeNB first data unwrap originate the most packets for giving UE number PDCP SN maximum magnitudes subtract 1 number According to bag number.If first packet PDCP SN=5HFN=10, source SeNB that such as purpose SeNB is received from source SeNB The packet for being sent to UE is up to PDCP SN=3HFN=11, thus UE from the source SeNB maximum data packets received be PDCP SN=3HFN=11.If the data UE that source SeNB is sent have received, UE expects that next packet received is PDCP SN=4HFN=11, the packet is packets of the corresponding first PDCP SN equal to 4 in purpose SeNB buffer, described The corresponding HFN of packet is 11.If packet some UE that source SeNB is sent are not received, if such as purpose SeNB is from UE The PDCP SN of next expectation are 9 in the PDCP states received, and the packet is corresponding first in purpose SeNB buffer Individual PDCP SN are equal to 9 packet, and purpose SeNB knows that corresponding HFN is 10.If so having phase in purpose SeNB caching With PDCP SN packet, then first packet for confiscating packet SN is in first corresponding UE PDCP state report Next packet for needing to be sent to UE, so purpose SeNB has been known that the corresponding HFN of the packet.

Or, for enhanced handoff procedure, it is next that purpose SeNB is included in thinking the PDCP states received from UE Half PDCP SN scopes of the PDCP SN of expectation not away from PDCP SN in the DL Count received in SN state Transfer Messages. If i.e. PDCP SN maximum is N, the N/2 of the PDCP SN of next expectation not away from PDCP SN in DL Count.Source SeNB to UE after have sent SN state Transfer Messages when sending data also in compliance with this principle.It is exemplified below：

● HFN=10 in DL COUNT, PDCP SN=8

● PDCP SN are 7 bits (SN scope is 0..127)

● when purpose SeNB from the PDCP SN of the UE next expectations received be 73..127 when, HFN=9

● when purpose SeNB from the PDCP SN of the UE next expectations received be 0..72 when, HFN=10

Source SeNB is after it have sent SN state Transfer Messages, and source SeNB is then sent to PDCP SN to UE transmissions data is 72, HFN be to stop sending downlink data packet after 10 to UE.

The enhanced handoff procedure of correspondence, if in the PDCP states that purpose SeNB is received from UE next expectation PDCP SN is 9, and purpose SeNB knows that corresponding HFN is 10.If not enhanced switching, purpose SeNB knows that corresponding HFN is 9.

Mode two：

In the PDCP state reports that UE is sent to purpose SeNB comprising it is next expectation receive the PDCP SN of packet with And the HFN corresponding to the PDCP SN.UE can be wrapped only in enhanced handoff procedure in the PDCP states for be sent to base station The HFN corresponding to the PDCP SN of packet is received containing next expectation.If not enhanced switching, purpose SeNB is according to existing Some principles know that next expectation receives the HFN corresponding to the PDCP SN of packet.

For split carryings, MeNB is known that UE reception state, therefore the corresponding data of transmission give purpose SeNB.

In order to solve the problem of upstream data is sent in the present invention, purpose SeNB is upper according to what is received in step 908b message Row reception state and up Count, the upstream data forwarded with reference to the source SeNB received, purpose SeNB update uplink receiving shape Uplink receiving state after renewal is sent to UE by state, purpose SeNB.Purpose SeNB needs to wait receives all turns from source SeNB New uplink receiving state is formed after the data of hair.Purpose SeNB knows that source SeNB is forwarded according to end mark (end marker) Be over data.The uplink receiving state of generation is sent to UE by purpose SeNB.UE is according to the uplink receiving received from purpose SeNB State, with reference to UE in the source SeNB data sent and the feedback received from source SeNB, is not received from next source SeNB Packet starts transmission upstream data and gives purpose SeNB.This method is carried for SCG.

For split carryings, whenever step 908a and step 908b can perform after step 903.

Step 910, MeNB sends UE context release request messages and gives source SeNB.

So far, that is, completing the application supports seamless handover method four and method five to be used for the description of dual link embodiment. The break period that data in handoff procedure are sent can be reduced by this method, it is ensured that up-downgoing data are continuously transmitted, it is to avoid Loss of data repeats to transmit.Particularly solve purpose SeNB and do not know asking for next corresponding HFN of PDCP SN that UE expects Topic, accordingly even when MeNB, source SeNB and purpose SeNB also ensure that the interoperability between base station from different manufacturers, it is ensured that Enhanced handoff procedure can workability simultaneously reduce handoff procedure in data send break period.

SeNB increases process in correspondence TS36.300 10.1.2.8.1 can also be determined to cut using enhanced by MeNB Process is changed, specific method includes step：

1) master base station determines to use enhanced handoff procedure, and informs SeNB by SeNB increase request messages.

2) enhanced indication message is included in SeNB by SeNB increases SeNB to the MeNB containers of request confirmation message In, UE is sent to by master base station.

3) master base station sends RRC reconfiguration request messages to UE, and the message package contains enhanced indication message.

4) UE is according to step 3) know it is enhanced handoff procedure.

Above-mentioned steps emphasis describes how to determine the method using enhanced handoff procedure, for the data hair of base station Give, data receiver, data forwarding it is similar with Fig. 7 and 9, detailed description is ignored here.

SeNB modifications process in correspondence TS36.300 10.1.2.8.2 can also be determined to cut using enhanced by MeNB Process is changed, specific method includes step：

1) master base station determines to use enhanced handoff procedure, and informs SeNB by SeNB modification request messages.

2) enhanced indication message is included in SeNB to the MeNB containers that SeNB changes request confirmation message by SeNB In, UE is sent to by master base station.

4) UE is according to step 3) know it is enhanced handoff procedure.

Switching is related to the process of SCG changes inside MeNB in correspondence TS36.300 10.1.2.8.2.1, can also be by MeNB To determine to use enhanced handoff procedure, specific method is same as described above, repeats no more here.

Correspondence TS36.300 10.1.2.8.3 SeNB releases process can also be determined to use enhanced switching by MeNB Process, specific method includes step：

1) master base station is determined to use enhanced handoff procedure, and (MeNB is initiated by SeNB releasing requests message SeNB discharge process) or SeNB release confirm (SeNB initiate SeNB release process) inform SeNB.

2) enhanced indication message is sent to UE by MeNB.

3) MeNB sends RRC reconfiguration request messages to UE, and the message package contains enhanced indication message.

4) UE is according to step 3) know it is enhanced handoff procedure.

Correspondence TS36.300 10.1.2.8.5 MeNB to eNB change procedures, can also be determined by source MeNB using increasing Strong handoff procedure, specific method includes step：

1) source master base station determines to use enhanced handoff procedure, and informs purpose eNB by handover request message.

2) purpose eNB is included in enhanced indication message in the RRC containers of switching request acknowledgement message, passes through source Master base station is sent to UE.

3) source master base station informs the enhanced indication messages of source SeNB by SeNB releasing requests.Source SeNB continues to send Data to UE and receive upstream data from UE.

4) source master base station sends RRC reconfiguration request messages to UE, and the message package contains enhanced indication message.

5) UE is according to step 4) know it is enhanced handoff procedure.

Correspondence TS36.300 10.1.2.8.7 eNB to MeNB change procedures, can also be determined by source eNB using enhancing Handoff procedure, specific method include step：

1) source base station determines to use enhanced handoff procedure, and informs purpose MeNB by handover request message.

2) purpose MeNB informs the enhanced indication messages of purpose SeNB by SeNB increase request messages.

3) enhanced indication message is included in SeNB and increased in the RRC containers for asking confirmation message by purpose SeNB. Purpose MeNB is included in enhanced indication message in the RRC containers of switching request acknowledgement message, is sent by source base station To UE.Or directly enhanced indication message is included in the RRC containers of switching request acknowledgement message by purpose MeNB, Enhanced indication message, which is included in SeNB, without purpose SeNB increases in the RRC containers for asking confirmation message.

4) source base station sends RRC reconfiguration request messages to UE, and the message package contains enhanced indication message.

5) UE is according to step 4) know it is enhanced handoff procedure.

Switching between correspondence TS36.300 10.1.2.8.8 differences MeNB scene constant SeNB, can also be by source MeNB come determine use enhanced handoff procedure, specific method be scene TS36.300 10.1.2.8.5 MeNB to eNB change The combination of process and TS36.300 10.1.2.8.7 eNB to MeNB change procedures, is repeated no more here.

The present invention supports the method six of seamless switching as described in Figure 10.The method comprising the steps of：

Step 1001, source base station (Source eNB) sends handover request message and gives purpose base station (Target eNB).

The message package is containing tenabilities of the UE to enhancing switching.UE supports the ability of enhanced switching to refer to UE in receipts To after RRC connection reconfiguration messages, the transmission reception state of source base station can not be frozen in, is not emptied two L2's of source base station layer Information, can continue to receive data from source base station or send data.Concrete meanings and step of the UE to the tenability of enhancing switching It is identical in rapid 701, repeat no more here.The UE may be embodied in radio resource control RRC to the tenability of enhancing switching In container Container.Source base station can also include an information element in handover request message：Support enhanced switched Journey.Source base station usually informs that purpose base station source base station supports enhanced switching with the information word, or is informed with the information element Purpose base station source base station and UE support enhanced handoff procedure.The implication for strengthening handoff procedure is identical with step 701, here Repeat no more.

Step 1002, purpose base station sends switching request acknowledgement message to source base station.

In this method, purpose base station determines to use enhanced handoff procedure.Purpose base station switched according to itself to enhancing The support of journey and UE ability determine to use enhanced handoff procedure.Or purpose base station according to itself to enhancing handoff procedure Support, UE ability and source base station the tenability of enhanced handoff procedure is determined use enhanced handoff procedure. Purpose base station can also consider the demand (for example quality of service ensures Qos information) of business simultaneously to determine to use enhanced switching Process.Purpose base station is also conceivable to other information to determine using enhanced handoff procedure without influenceing the present invention's main interior Hold.Purpose base station obtains tenabilities of the UE to enhancing switching from source base station.Matched somebody with somebody by operation and maintenance (O＆M's) purpose base station Put or X2 sets up process to know tenability of the source base station to enhanced handoff procedure.Correspondence sets up the side of process by X2 Method, sets up request in X2 and X2 sets up in response message support of the base station for including the transmission message to enhanced handoff procedure Ability.Receive X2 and set up the opposite end base station for asking to receive with the base station holding that X2 sets up response message to enhanced handoff procedure Tenability.Source base station comprising one in handover request message by supporting enhanced handoff procedure to believe in correspondence step 1001 Breath member usually informs the method that purpose base station source base station and UE support enhanced handoff procedure, and purpose base station passes through the institute that receives Information element is stated it is known that source base station and UE support enhanced handoff procedure.

There are following methods that source base station can be allowed to know in the present invention and use enhanced handoff procedure.

Method one, purpose base station comprising enhanced indication message in switching request acknowledgement message by allowing source base station Use enhanced handoff procedure.The switching enhancing instruction is also contained in purpose base station into the RRC containers of source base station, passes through source Base station is sent to UE

Method two, includes enhanced indication message in RRC containers.Source base station is to receive described handover request true Recognize after message, it is enhanced handoff procedure that notice, which checks that RRC containers are known,.RRC containers are sent to UE by source base station can allow UE It is enhanced handoff procedure to know the handoff procedure.

Step 1003, source base station sends RRC connection reconfiguration messages to UE.Indicated in the message comprising enhanced switching Information.The enhanced handoff procedure of correspondence, source base station continues to send downlink data to UE.A kind of method of the correspondence present invention, source base The packet that station continues to be sent to UE is to unwrap a beginning up to PDCP SN most from first data for being transmitted to purpose base station The a wide range of packet for subtracting 1 number.First packet that such as source base station is transmitted to purpose base station is that PDCP SN are equal to 5, HFN is 10, then it is 11 that source base station is up to PDCP SN equal to 3, HFN to the UE packets sent.Source base station is according to step 1002 In the enhanced indication message that receives or known by the enhanced configured information seen in RRC containers cut using enhanced Change process.

In order to solve the problem of upstream data is sent in the present invention, correspondence one of which method, source base station this step it Continue the data receiving state of feeding back uplink afterwards or after step 1004 to UE.So UE is known that source base station has been received from UE Which packet.So after the message of UE forwarding steps 1006, it is known that since which packet and sends data to mesh Base station.

Step 1004, the source base station SN states that transmit Sequence Number are transferred to purpose base station.

Source base station can notify purpose base station strengthens to be unwrapped in handoff procedure from first data for being transmitted to purpose base station Originate the number for the most packets for giving UE, e.g. PDCP SN maximum magnitudes subtract 1 number packet or other.Example If as PDCP SN be the packet for subtracting 1 number from 0 to 127, PDCP SN maximum magnitudes be 127 PDCP SDU or PDU。

In this step, source base station does not freeze to send and receive state.

Source base station starts to forward data to purpose base station.The downlink data for being sent to UE is also transmitted to purpose base by source base station Stand.

Source base station from the UE upstream data packets received being transmitted to purpose base station.A kind of method is source base station SN shapes Received after state Transfer Message tactic does not receive upstream data bag sequentially and is forwarded to purpose base station.Another side Method is that the packet sequentially received is sent to SGW by source base station, and the packet not received sequentially is transmitted to purpose base station.

Step 1005, UE is synchronized to purpose base station.UE accesses purpose cell by RACH RACH.

In the present invention, UE can stop receiving downlink data from source base station in this step, stop at source base station and send up Data.It can also stop receiving downlink data from source base station in step 1006, stop at source base station and send upstream data.

In order to solve the problem of upstream data is sent in the present invention, purpose base station is upper according to what is received in step 1004 message In row reception state and up Count, the upstream data forwarded with reference to the source base station received from source base station, the renewal of purpose base station Uplink receiving state after renewal is sent to UE by row reception state, purpose base station.If purpose base station is gone back after RACH successes Continue to receive the data forwarded from source base station, purpose base station, which needs to wait to receive from source base station, forms new after the data of all forwardings Uplink receiving state.Know that source base station forwards the data that are over according to end mark (end marker) in purpose base station.

Step 1006, UE transmissions RRC connections reconfigure completion message and give purpose base station.Since after step 1003, source base Standing-meeting sends downlink data and gives purpose base station to UE and converting downlink data simultaneously.So turn that purpose base station is received from source base station The possible UE of some in the data of hair have received.Purpose base station, which has following mode to detect, need not be sent to UE number According to：

Purpose base station determines that this switching uses enhanced handoff procedure in step 1002.Switched for enhanced Journey, purpose base station sends data to UE according to the method for enhanced handoff procedure and/or sends upstream data to SGW.Purpose base Stand and determine that UE expects next corresponding HFN of PDCP SN for receiving packet according to enhanced handoff procedure.

Or, the PDCP SN of next expectation that purpose base station is included in thinking the PDCP states received from UE not away from PDCP SN half PDCP SN scopes in the DL Count received in SN state Transfer Messages.If i.e. PDCP SN maximum Value is N, then N/2s of the PDCP SN of next expectation not away from PDCP SN in DL Count.Source base station have sent SN states When sending data to UE also in compliance with this principle after Transfer Message.It is exemplified below：

● HFN=10 in DL COUNT, PDCP SN=8

● PDCP SN are 7 bits (SN scope is 0..127)

In order to solve the problem of upstream data is sent in the present invention, purpose base station is upper according to what is received in step 1004 message In row reception state and up Count, the upstream data forwarded with reference to the source base station received from source base station, the renewal of purpose base station Uplink receiving state after renewal is sent to UE by row reception state, purpose base station.Purpose base station needs to wait receives from source base station New uplink receiving state is formed after to the data of all forwardings.Purpose base station source is known according to end mark (end marker) Base station forwards the data that are over.The uplink receiving state of generation is sent to UE by purpose base station.

Step 1007, transmitting path handover request message in purpose base station is to MME.

Step 1008, MME transmitting pathes handover request ack message gives purpose base station.

Step 1009, purpose base station sends UE context release messages to source base station.

So far, that is, the description that the present invention supports seamless handover method six is completed.It can be reduced and switched by this method The break period that data are sent in journey, it is ensured that up-downgoing data are continuously transmitted, it is to avoid loss of data repeats to transmit.Particularly The problem of next PDCP SN for solving purpose base station not know that UE expects corresponding HFN, accordingly even when source base station and purpose base Stand from different manufacturers, also ensure that the interoperability between two base stations, it is ensured that enhanced handoff procedure can workability simultaneously Reduce the break period that data are sent in handoff procedure.

Figure 11 supports the method six of seamless switching to be used for the embodiment schematic diagram of dual link for the present invention.Including step：

Step 1101, master base station (MeNB) sends the second base station (SeNB) increase request message and gives purpose SeNB (T- SeNB)。

The message package is containing tenabilities of the UE to enhancing switching.UE refers to that UE is supported to the tenability of enhancing switching Holding and the handoff procedure of source base station connection that 3GPP Rel-14 are discussed.Concretely, UE supports the ability of enhanced switching to refer to Be UE after RRC connection reconfiguration messages are received, source SeNB transmission reception state can not be frozen in, do not emptied in source The L2 of SeNB layers two information, can continue to receive data from source SeNB or send data.Branch of the more specifically UE to enhancing switching Hold the concrete meaning of ability identical with step 701, repeat no more here.The UE can be wrapped to the tenability of enhancing switching It is contained in radio resource control RRC container Container.Here RRC containers refer to MeNB to SeNB containers.Master base station An information element can be included in SeNB increase request messages：Support enhanced handoff procedure.The master base station information word Usually inform that purpose SeNB master base stations support enhanced switching, or purpose SeNB master base stations and UE are informed all with the information element Support enhanced handoff procedure.The implication for strengthening handoff procedure is identical with step 901, repeats no more here.

Step 1102, T-SeNB sends SeNB increase request confirmation messages to MeNB.

In this method, purpose SeNB determines to use enhanced handoff procedure.Abilities of the purpose SeNB according to UE, master base station pair Tenability, source SeNB and/or the purpose SeNB for strengthening switching decide whether using enhancing to the tenability of enhancing switching Switching.Purpose SeNB is also conceivable to other information such as Qos to determine using enhanced switching without influenceing the present invention's Main contents.Purpose SeNB obtains tenabilities of the UE to enhancing switching from master base station.Purpose SeNB passes through operation and maintenance (O＆ M configuration or X2) sets up process to know the tenability of master base station and source SeNB to enhanced handoff procedure.Correspondence passes through X2 The method for setting up process, sets up in X2 and asks to cut to enhanced with the base station that X2 is set up comprising the transmission message in response message Change the tenability of process.Receive X2 and set up the opposite end base station for asking to receive with the base station holding that X2 sets up response message to enhancing Handoff procedure tenability.Comprising a support during master base station in SeNB by increasing request message in correspondence step 1101 Enhanced handoff procedure information word usually informs the method that purpose SeNB master base stations and UE support enhanced handoff procedure, purpose SeNB is by the described information element that receives it is known that master base station and UE support enhanced handoff procedure.

There are following methods that master base station can be allowed to know in the present invention and use enhanced handoff procedure.

Method one, purpose SeNB comprising enhanced indication message in SeNB increase request confirmation messages by allowing master Base station uses enhanced handoff procedure.The switching enhancing instruction is also contained in SeNB to MeNB containers, is sent out by master base station Give UE.

Method two, includes enhanced indication message in SeNB to MeNB containers.Master base station receive it is described After SeNB increase request confirmation messages, it is enhanced handoff procedure that notice, which checks that SeNB to MeNB containers are known,.Master base station handle SeNB to MeNB containers, which are sent to UE, can allow UE to know that the handoff procedure is enhanced handoff procedure.

Step 1103, if T-SeNB resource allocation success, MeNB sends SeNB releasing requests message and gives source SeNB (S- SeNB).If necessary to data forwarding, MeNB provides data forwarding addresses to S-SeNB.

Method one：Master base station comprising enhanced indication message in SeNB releasing request message by allowing source SeNB to know This switching of road is enhanced handoff procedure.Master base station knows that the process is enhanced handoff procedure according to step 1102.

Method two：Comprising tenabilities of the UE to enhancing switching in SeNB increases release message, if source SeNB is supported Enhanced handoff procedure, source SeNB is according to master base station and/or purpose SeNB to the tenability of enhancing handoff procedure and UE pairs The tenability of enhancing switching knows that this handoff procedure is enhanced handoff procedure.MeNB obtains UE to enhancing switching from UE Tenability.Source SeNB sets up process to know SeNB pairs of master base station/or purpose by the configuration or X2 of operation and maintenance (O＆M) The tenability of enhanced handoff procedure.The method that correspondence sets up process by X2, sets up request in X2 and X2 sets up response and disappeared Tenability of the base station to enhanced handoff procedure for sending the message is included in breath.Receive X2 and set up request and X2 foundation sound The base station of message is answered to keep the opposite end base station that receives to the tenability of enhanced handoff procedure.This method of correspondence, it is assumed that such as Fruit master base station and source SeNB and purpose SeNB support enhanced handoff procedure, are initiated when described to supporting to strengthen the UE's switched During handoff procedure, enhanced handoff procedure will be initiated.

For SCG carryings, S-SeNB continues the data receiving state of feeding back uplink to UE after this step.So UE is just Know which packet S-SeNB have received from UE.Which so after the message of UE forwarding steps 1107, it is known that from Packet starts to send data to purpose SeNB.

Step 1104, MeNB sends RRC connection reconfiguration messages to UE.In the message letter is indicated comprising enhanced switching Breath.MeNB continues to send downlink data to S-SeNB.MeNB converting downlink data are to T-SeNB simultaneously.One kind of the correspondence present invention Method, the packet that source SeNB continues to be sent to UE is to unwrap the beginning up to one from first data for being transmitted to purpose SeNB The packet number of PDCP SN maximum magnitudes subtracts 1.First packet that such as source SeNB is transmitted to purpose SeNB is PDCP It is 10 that SN, which is equal to 5, HFN, then it is 11 that source SeNB is up to PDCP SN equal to 3, HFN to the UE packets sent.

Step 1105, UE sends RRC connections and reconfigures completion message to MeNB.

Step 1106, MeNB sends SeNB and reconfigures completion message to T-SeNB.

Step 1107, UE is synchronized to T-SeNB.

Step 1108a, S-SeNB transmission SN states are transferred to MeNB.

Step 1108b, MeNB transmission SN states are transferred to T-SeNB.

Step 1109, S-SeNB forwards data to T-SeNB.Correspondence split carryings, S-SeNB forwards data to MeNB, by MeNB is transmitted to T-SeNB., can be as split carryings for SCG carryings, S-SeNB is transmitted to T-SeNB by MeNB, Or S-SeNB is directly forwarded to T-SeNB.Depending on realization, S-SeNB forwards data to T-SeNB can be after step 103 Whenever perform.

Because after step 1103, source SeNB can send downlink data simultaneously to UE and converting downlink data to purpose SeNB.So purpose SeNB some possible UE from the data of the source SeNB forwardings received have received.Purpose SeNB UE data need not be sent to by being detected by following mode：

Mode one：

Using the method described in step 1101, purpose SeNB is known that whether this switching is enhanced switched Journey.For enhanced handoff procedure, purpose SeNB is sent data on UE and/or transmission according to the method for enhanced handoff procedure Row data are to SGW.

Mode two：

In order to solve the problem of upstream data is sent in the present invention, purpose SeNB in step 1108b message according to receiving Uplink receiving state and up Count, the upstream data forwarded with reference to the source SeNB received, purpose SeNB update uplink receiving Uplink receiving state after renewal is sent to UE by state, purpose SeNB.It is all that purpose SeNB needs wait to be received from source SeNB New uplink receiving state is formed after the data of forwarding.Purpose SeNB knows that source SeNB turns according to end mark (end marker) Data are distributed.The uplink receiving state of generation is sent to UE by purpose SeNB.UE up connects according to what is received from purpose SeNB Receipts state, with reference to UE in the source SeNB data sent and the feedback received from source SeNB, is not received from next source SeNB Packet start send upstream data give purpose SeNB.This method is carried for SCG.

For split carryings, whenever step 1108a and step 1108b can perform after step 903.

Step 1110, MeNB sends UE context release request messages and gives source SeNB.

SeNB increases process in correspondence TS36.300 10.1.2.8.1 can also be determined to cut using enhanced by SeNB Process is changed, specific method includes step：

1) SeNB determines to use enhanced handoff procedure.

3) there is two ways to allow master base station to know and use enhanced handoff procedure.Mode one is master base station parsing SeNB increases Enhancing indication message in request confirmation message in SeNB to MeNB containers knows it is enhanced switching.Mode two is SeNB Enhancing indication message is also asked in confirmation message included in SeNB increases simultaneously.Master base station is true by SeNB increase requests The enhancing indication message recognized in message is without parsing RRC containers it is known that SeNB is determined is cut using enhanced Change process.

4) master base station sends RRC reconfiguration request messages to UE, and the message package contains enhanced indication message.

5) UE is according to step 4) know it is enhanced handoff procedure.

Above-mentioned steps emphasis describes how to determine the method using enhanced handoff procedure, for the data hair of base station Give, data receiver, data forwarding it is similar with Figure 10 and 11, detailed description is ignored here.

The SeNB modifications process that MeNB and SeNB in correspondence TS36.300 10.1.2.8.2 are initiated can also by SeNB Lai Determine to use enhanced handoff procedure, specific method includes step：

1) SeNB determines to use enhanced handoff procedure.

3) there is two ways to allow master base station to know and use enhanced handoff procedure.Mode one is master base station parsing SeNB modifications Enhancing indication message in request confirmation message in SeNB to MeNB containers knows it is enhanced switching.Mode two is SeNB Enhancing indication message is also asked in confirmation message included in SeNB modifications simultaneously.Master base station is true by SeNB modification requests The enhancing indication message recognized in message is without parsing RRC containers it is known that SeNB is determined is cut using enhanced Change process.

5) UE is according to step 4) know it is enhanced handoff procedure.

The SeNB modifications process that SeNB in correspondence TS36.300 10.1.2.8.2 is initiated can also be determined to make by SeNB Enhanced handoff procedure is used, specific method includes step：

1) SeNB determines to use enhanced handoff procedure.

2) SeNB arrives the SeNB that enhanced indication message is included in SeNB modification demand (Required) message In MeNB containers, UE is sent to by master base station.

3) there is two ways to allow master base station to know and use enhanced handoff procedure.Mode one is master base station parsing SeNB modifications It is enhanced switching that enhancing indication message in requirement validation message in SeNB to MeNB containers, which is known,.Mode two is SeNB Enhancing indication message is also changed in requirement validation message included in SeNB simultaneously.It is true that master base station changes demand by SeNB The enhancing indication message recognized in message is without parsing RRC containers it is known that SeNB is determined is cut using enhanced Change process.

5) UE is according to step 4) know it is enhanced handoff procedure.

Switching is related to the process of SCG changes inside MeNB in correspondence TS36.300 10.1.2.8.2.1, can also be by SeNB To determine to use enhanced handoff procedure, specific method is same as described above, repeats no more here.

Correspondence TS36.300 10.1.2.8.5 MeNB to eNB change procedures, can also be determined by purpose eNB using increasing Strong handoff procedure, specific method includes step：

1) purpose eNB determines to use enhanced handoff procedure.

3) there is two ways to allow source master base station to know and use enhanced handoff procedure.Mode one is source master base station parsing switching Enhancing indication message in request confirmation message in RRC containers knows it is enhanced switching.Mode two is purpose eNB increasing Strong indication message is also simultaneously included in switching request acknowledgement message.Source master base station passes through in switching request acknowledgement message Enhancing indication message is without parsing RRC containers it is known that purpose eNB, which is determined, uses enhanced handoff procedure.

4) source master base station informs the enhanced indication messages of source SeNB by SeNB releasing requests.Source SeNB continues to send Data to UE and receive upstream data from UE.

5) source master base station sends RRC reconfiguration request messages to UE, and the message package contains enhanced indication message.

6) UE is according to step 5) know it is enhanced handoff procedure.

Correspondence TS36.300 10.1.2.8.7 eNB to MeNB change procedures, can also be determined to use by purpose MeNB Enhanced handoff procedure, specific method includes step：

1) purpose MeNB determines to use enhanced handoff procedure.Purpose MeNB determines to use after handover request message is received Enhanced handoff procedure.

5) UE is according to step 4) know it is enhanced handoff procedure.

Correspondence TS36.300 10.1.2.8.7 eNB to MeNB change procedures, can also be determined to use by purpose SeNB Enhanced handoff procedure, specific method includes step：

1) purpose SeNB determines to use enhanced handoff procedure.Purpose MeNB is determined after SeNB increase request messages are received Use enhanced handoff procedure.

2) enhanced indication message is included in SeNB and increased in the RRC containers for asking confirmation message by purpose SeNB. Purpose MeNB is included in enhanced indication message in the RRC containers of switching request acknowledgement message, is sent by source base station To UE.Or purpose SeNB informs the enhanced indication messages of purpose MeNB by SeNB increase request confirmation messages, by mesh MeNB enhanced indication message be included in switching request acknowledgement message RRC containers in, without purpose SeNB Enhanced indication message is included in the RRC containers that SeNB increases request confirmation message.There is two ways to allow source base station Use enhanced switching：

Enhancing indication message in mode one, the RRC containers of source base station parsing switching request acknowledgement message, which is known, to be made With enhanced switching.

Mode two, increases request in SeNB and confirms to include enhanced switching in the X2 access layer informations with Handover Request Acknowledge Configured information, allows source base station to know using enhanced switching, without parsing the RRC containers in switching request acknowledgement message.

3) source base station sends RRC reconfiguration request messages to UE, and the message package contains enhanced indication message.

4) UE is according to step 3) know it is enhanced handoff procedure.

Switching between correspondence TS36.300 10.1.2.8.8 differences MeNB scene constant SeNB, can also be by purpose MeNB come determine use enhanced handoff procedure, specific method be scene TS36.300 10.1.2.8.5 MeNB to eNB change The combination of process and TS36.300 10.1.2.8.7 eNB to MeNB change procedures, is repeated no more here.

The first specific embodiment of correspondence of the embodiment of the present invention, also provides a kind of base station equipment, is source base station, including：First Sending module, first processing module and the first receiving module, wherein,

First receiving module, the upstream data for continuing to UE；Receive and sent out after UE is synchronized to the purpose base station The data sent, which are sent, to be stopped indicating, indicates that first processing module is handled；Receive and composed a piece of writing on the UE that the purpose base station is sent Release message；

The first specific embodiment of correspondence of the embodiment of the present invention, also provides a kind of base station equipment, is purpose base station, including：

Second sending module and the second receiving module, wherein,

The second specific embodiment of correspondence of the embodiment of the present invention, also provides a kind of base station equipment, is source base station, including：3rd Sending module, the 3rd processing module and the 3rd receiving module, wherein,

The second specific embodiment of correspondence of the embodiment of the present invention, also provides a kind of base station equipment, is purpose base station, including：The Four sending modules and the 4th receiving module, wherein,

The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all essences in the present invention God is with principle, and any modification, equivalent substitution and improvements done etc. should be included within the scope of protection of the invention.

Claims

1. a kind of method for supporting seamless switching, this method includes：

RRC connection reconfiguration messages are sent to UE, continues to send downlink data to UE, continues to the upstream data of UE transmissions；

The data transmission stopping instruction that the purpose base station is sent is received, the source base station stops sending downlink data to UE, stopped Only upstream data is received from UE；

Receive the UE context release messages that the purpose base station is sent.

2. according to the method described in claim 1, it is characterised in that also comprising step：

3. method according to claim 2, it is characterised in that the 2nd SN state Transfer Messages are included：

Or descending PDCP SN and/or HFN transmission state.

4. according to the method described in claim 1, it is characterised in that the source base station send RRC connection reconfiguration messages to UE, or the source base station send SN states and are transferred to after purpose base station, and this method also includes：

Source base station is to UE feeding back uplink data receiving states.

5. method according to claim 2, it is characterised in that the source base station send the 2nd SN states Transfer Message to In the step of purpose base station, in addition to：

Or, source base station will stop the uplink receiving state after upstream data is received and up COUNT is sent to purpose base station.

6. method according to claim 5, it is characterised in that send SN states in the source base station and be transferred to purpose base station Afterwards and before the source base station sends the 2nd SN states Transfer Message to purpose base station, or in source base station transmission SN State is transferred to after purpose base station and before the data for receiving the transmission of purpose base station send stopping instruction, and this method is also wrapped Include：

7. according to the method described in claim 1, it is characterised in that the step of source base station forwards data to purpose base station In, the data are：

Using the order of the packet of the SN mark forwardings in GTP-U；

Or, comprising the packet for defining Frame Protocol FP, wherein, FP data division includes the PDCP packets of forwarding, FP's The serial number of the packet is included in packet header；

Or, include PDCP SN packet, wherein, the PDCP SN that first packet is used be the particular value that sets or It is the false of setting；

8. a kind of base station equipment, it is characterised in that including：First sending module, first processing module and the first receiving module, its In,

First sending module, purpose base station is given for sending handover request message；RRC connection reconfiguration messages are sent to UE, after Supervention send downlink data to UE；Send SN states and be transferred to purpose base station, start to forward data to the purpose base station；

First receiving module, the upstream data for continuing to UE；Receive the data transmission stopping that the purpose base station is sent Indicate, indicate that first processing module is handled；Receive release message of being composed a piece of writing on the UE that the purpose base station is sent；

First processing module, downlink data is sent to UE for controlling the first sending module to stop under the instruction of receiving module, And control the first receiving module to stop receiving upstream data from UE.

9. a kind of method for supporting seamless switching, this method includes：

Purpose base station is received after the handover request message of source base station transmission, and switching request acknowledgement message is sent to source base station；

Receive the SN states transfer that transmits Sequence Number that the source base station is sent after RRC connection reconfiguration messages are sent to UE；

After UE is synchronized to the purpose base station, the purpose base station sends data transmission stopping and is indicated to the source base station；

10. method according to claim 9, it is characterised in that also comprising step：

Mode one：Purpose base station is according to the PDCP SN and/or HFN received in the 2nd SN state Transfer Messages from source base station hair Send state that repeated data is abandoned, directly transmit the data that UE is not received, described repeated data refers to source base station simultaneously It is sent to UE and is transmitted to the data of purpose base station；

Mode two：Purpose base station detects that what is repeated need not be sent to UE number according to from the UE PDCP state reports received According to discarding repeated data directly transmits the data that UE is not received；

Mode three, the PDCP state reports that purpose base station combines the 2nd SN states Transfer Message and received from UE detect to repeat Need not be sent to UE data, abandon repeated data, directly transmit the data that UE is not received, the 2nd SN states turn Moving message includes PDCP SN and/or HFN transmission state.

11. a kind of method for supporting seamless switching, this method includes：

Source base station sends handover request message and gives purpose base station, receives the switching request acknowledgement message that the purpose base station is sent；

Receive the purpose base station and stop indicating receiving RRC links and reconfigure the data that send after completion message and send, stop Downlink data is only sent to UE；

Receive the UE context release messages that the purpose base station is sent.

12. method according to claim 11, it is characterised in that also comprising step,

The source base station receives the upstream data stopping reception instruction that purpose base station is sent after the synchronizing information of UE transmissions is received, The source base station stops receiving upstream data from UE；

In the case where the step is not performed, the source base station stops connecing from UE when receiving the message that data transmission stopping is indicated Data above and below receipts.

13. a kind of base station equipment, it is characterised in that including：3rd sending module, the 3rd processing module and the 3rd receiving module, Wherein,

3rd sending module, purpose base station is given for sending handover request message；RRC connection reconfiguration messages are sent to UE, after Supervention send downlink data to UE；Send SN states and be transferred to purpose base station, start to forward data to the purpose base station；

3rd receiving module, for receiving the switching request acknowledgement message that the purpose base station is sent, continues to the up of UE Data；Receive the purpose base station and stop indicating receiving RRC links and reconfigure the data that send after completion message and send, refer to Show that the 3rd processing module is handled；Receive release message of being composed a piece of writing on the UE that the purpose base station is sent；

3rd processing module, downlink data is sent to UE for controlling sending module to stop under the instruction of the 3rd receiving module, And control the 3rd receiving module to stop receiving upstream data from UE.

14. a kind of method for supporting seamless switching, this method includes：

The RRC connections for receiving the UE transmissions reconfigure completion message, send data transmission stopping and are indicated to the source base station；

To MME transmitting path handover request message；

15. a kind of method of support seamless switching for dual link, this method includes：

The resource allocation success of purpose base station, MeNB sends base station releasing request message to source base station, and source base station continues to send Downlink data, and source base station forwards the data to purpose base station；

MeNB sends RRC connection reconfiguration messages to UE, and MeNB continues to send downlink data to source base station, MeNB converting downlink numbers According to giving purpose base station；

UE receives RRC connection reconfiguration messages, and UE does not delete or be reset at the configuration of source base station, and between source base station in continuation Downlink data transmission, UE sends RRC connections and reconfigures completion message to MeNB；

Purpose base station sends data transmission stopping and is indicated to MeNB, and MeNB, which is received, stops sending downlink data to source after the message Base station, MeNB sends data transmission stopping and is indicated to source base station；

Source base station sends SN states and is transferred to MeNB.

MeNB sends SN states and is transferred to purpose base station.